diff --git a/.github/workflows/ruby-backward-compatibility.yml b/.github/workflows/ruby-backward-compatibility.yml
new file mode 100644
index 000000000..1818021ac
--- /dev/null
+++ b/.github/workflows/ruby-backward-compatibility.yml
@@ -0,0 +1,43 @@
+name: Ruby specs - Backward compatibility
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    name: Ruby specs - Backward compatibility
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+        ruby: ['2.6', '2.7', '3.0']
+        gemfile:
+          - gemfiles/Gemfile-rails.5.2.x
+          - gemfiles/Gemfile-rails.6.0.x
+          - gemfiles/Gemfile-rails.6.1.x
+          - gemfiles/Gemfile-rails.7.0.x
+          # Uncomment the following line only to ensure compatibility with the
+          # upcomming Rails versions, maybe before a release.
+          #- gemfiles/Gemfile-rails-edge
+        exclude:
+          - ruby: 2.6
+            os: ubuntu-latest
+            gemfile: gemfiles/Gemfile-rails.7.0.x
+          - ruby: 2.6
+            os: ubuntu-latest
+            gemfile: gemfiles/Gemfile-rails-edge
+          - ruby: 3.0
+            os: ubuntu-latest
+            gemfile: gemfiles/Gemfile-rails.5.2.x
+
+    env:
+      BUNDLE_GEMFILE: ${{ matrix.gemfile }}
+
+    steps:
+      - uses: actions/checkout@v2
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler-cache: true
+
+      - name: Ruby specs - Backward compatibility
+        run: bundle exec rake test_bc
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 905e21b92..6d4f59a03 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,5 @@
 * For the changelog of versions prior to v6, see the [5.x stable branch of rails/webpacker](https://github.com/rails/webpacker/tree/5-x-stable).
+* Please see the [v7 Upgrade Guide](./docs/v7_upgrade.md) for upgrading to new spelling in version 7.
 * Please see the [v6 Upgrade Guide](./docs/v6_upgrade.md) to go from versions prior to v6.
 * [ShakaCode](https://www.shakacode.com) offers support for upgrading from Webpacker or using Shakapacker. If interested, contact Justin Gordon, [justin@shakacode.com](mailto:justin@shakacode.com).
 
@@ -18,6 +19,36 @@ _Please add entries here for your pull requests that are not yet released._
 ### Improved
 - Move compilation lock file into the working directory. [PR 272](https://github.com/shakacode/shakapacker/pull/272) by [tomdracz](https://github.com/tomdracz).
 
+### Changed
+- Rename Webpacker to Shakapacker in the entire project including config files, binstubs, environment variables, etc. with a high degree of backward compatibility.
+
+  This change might be breaking for certain setups and edge cases. More information: [v7 Upgrade Guide](./docs/v7_upgrade.md) [PR157](https://github.com/shakacode/shakapacker/pull/157) by [ahangarha](https://github.com/ahangarha)
+- Set `source_entry_path` to `packs` and `nested_entries` to `true` in`shakapacker.yml` [PR 284](https://github.com/shakacode/shakapacker/pull/284) by [ahangarha](https://github.com/ahangarha).
+
+### Fixed
+- Process `source_entry_path` with values starting with `/` as a relative path to `source_path` [PR 284](https://github.com/shakacode/shakapacker/pull/284) by [ahangarha](https://github.com/ahangarha).
+
+- Dev server configuration is modified to follow [webpack recommended configurations](https://webpack.js.org/configuration/dev-server/) for dev server. [PR276](https://github.com/shakacode/shakapacker/pull/276) by [ahangarha](https://github.com/ahangarha):
+  - Deprecated `https` entry is removed from the default configuration file, allowing to set `server` or `https` as per the project requirements. For more detail, check Webpack documentation. The `https` entry can be effective only if there is no `server` entry in the config file.
+  - `allowed_hosts` is now set to `auto` instead of `all` by default.
+
+- Removes defaults passed to `@babel/preset-typescript`. [PR 273](https://github.com/shakacode/shakapacker/pull/273) by [tomdracz](https://github.com/tomdracz).
+
+  `@babel/preset-typescript` has been initialised in default configuration with `{ allExtensions: true, isTSX: true }` - meaning every file in the codebase was treated as TSX leading to potential issues. This has been removed and returns to sensible default of the preset which is to figure out the file type from the extensions. This change might affect generated output however so it is marked as breaking.
+
+- Remove the arbitrary stripping of the top-level directory when generating static file paths. [PR 283](https://github.com/shakacode/shakapacker/pull/283) by [tomdracz](https://github.com/tomdracz).
+
+  Prior to this change, top level directory of static assets like images and fonts was stripped. This meant that file in `app/javascript/images/image.png` would be output to `static/image.png` directory and could be referenced through helpers as `image_pack_tag("image.jpg")` or `image_pack_tag("static/image.jpg")`.
+
+  Going forward, the top level directory of static files will be retained so this will necessitate the update of file name references in asset helpers. In the example above, the file sourced from `app/javascript/images/image.png` will be now output to `static/images/image.png` and needs to be referenced as `image_pack_tag("images/image.jpg")` or `image_pack_tag("static/images/image.jpg")`.
+
+### Removed
+- Remove redundant enhancement for precompile task to run `yarn install` [PR 270](https://github.com/shakacode/shakapacker/pull/270) by [ahangarha](https://github.com/ahangarha).
+
+### Added
+- All standard Webpack entries with the camelCase format are now supported in `shakapacker.yml` in snake_case format. [PR276](https://github.com/shakacode/shakapacker/pull/276) by [ahangarha](https://github.com/ahangarha).    
+
+
 ## [v6.6.0] - March 7, 2023
 ### Improved
 - Allow configuration of webpacker.yml through env variable. [PR 254](https://github.com/shakacode/shakapacker/pull/254) by [alecslupu](https://github.com/alecslupu).
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 30dbaf8ad..922341fe7 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -49,21 +49,21 @@ bundle exec rake test
 #### 4.1 Run a single ruby test file
 
 ```
-bundle exec rake test TEST=test/rake_tasks_test.rb
+bundle exec rspec spec/configuration_spec.rb
 ```
 
 #### 4.2 Run a single ruby test
 
 ```
-bundle exec ruby -I test test/rake_tasks_test.rb -n test_rake_webpacker_install
+bundle exec rspec -e "#source_entry_path returns correct path"
 ```
 
 ## Testing the generator
 If you change the generator, check that install instructions work.
 
-1. Update the gemfile so that gem "webpacker" has a line like this, pointing to your install of webpacker
+1. Update the gemfile so that gem "shakapacker" has a line like this, pointing to your install of shakapacker
    ```ruby
-   gem 'webpacker', path: "~/shakacode/forks/shakapacker"
+   gem 'shakapacker', path: "~/shakacode/forks/shakapacker"
    ```
 2. `bundle`
 3. Run the generator confirm that you got the right changes. 
diff --git a/README.md b/README.md
index 111264f01..60f68358f 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,8 @@
 # Shakapacker
 
-_Official, actively maintained successor to [rails/webpacker](https://github.com/rails/webpacker). Internal naming for `shakapacker` will continue to use `webpacker` where possible for v6. ShakaCode stands behind the long-term maintainence and development of this project for the Rails community._
+_Official, actively maintained successor to [rails/webpacker](https://github.com/rails/webpacker).ShakaCode stands behind the long-term maintenance and development of this project for the Rails community._
 
+* See [V7 Upgrade](./docs/v7_upgrade.md) for upgrading from v6 release.
 * See [V6 Upgrade](./docs/v6_upgrade.md) for upgrading from v5 or prior v6 releases.
 
 [![Ruby specs](https://github.com/shakacode/shakapacker/workflows/Ruby%20specs/badge.svg)](https://github.com/shakacode/shakapacker/actions)
@@ -15,7 +16,7 @@ _Official, actively maintained successor to [rails/webpacker](https://github.com
 
 Shakpacker makes it easy to use the JavaScript pre-processor and bundler [Webpack v5+](https://webpack.js.org/)
 to manage frontend JavaScript in Rails. It can coexist with the asset pipeline,
-leaving Webpack responsible solely for frontend JavaScript, or  can be used exclusively, making it also responsible for images, fonts, and CSS.
+leaving Webpack responsible solely for frontend JavaScript, or can be used exclusively, making it also responsible for images, fonts, and CSS.
 
 Check out 6.1.1+ for [SWC](https://swc.rs/) and [esbuild-loader](https://github.com/privatenumber/esbuild-loader) support! They are faster than Babel!
 
@@ -26,7 +27,7 @@ For discussions, see our [Slack Channel](https://reactrails.slack.com/join/share
 ---
 ### ShakaCode Support
 
-[ShakaCode](https://www.shakacode.com) offers support for upgrading from webpacker and using Shakapacker. If interested, contact Justin Gordon, [justin@shakacode.com](mailto:justin@shakacode.com). We're also [hiring](https://jobs.lever.co/shakacode/3bdbfdb3-4495-4611-a279-01dddb351abe)!
+[ShakaCode](https://www.shakacode.com) offers support for upgrading from Webpacker and using Shakapacker. If interested, contact Justin Gordon, [justin@shakacode.com](mailto:justin@shakacode.com). We're also [hiring](https://jobs.lever.co/shakacode/3bdbfdb3-4495-4611-a279-01dddb351abe)!
 
 Here's a testimonial of how ShakaCode can help, from [Florian Gößler](https://github.com/FGoessler) of [Blinkist](https://www.blinkist.com/), January 2, 2023:
 > Hey Justin 👋
@@ -102,8 +103,8 @@ Read the [full review here](https://clutch.co/profile/shakacode#reviews?sort_by=
 
 ## Features
 - Rails view helpers that fully support Webpack output, including HMR and code splitting.
-- Convenient but not required webpack configuration. The only requirement is that your webpack configuration create a manifest.
-- HMR with the webpack-dev-server, such as for hot-reloading React!
+- Convenient but not required webpack configuration. The only requirement is that your webpack configuration creates a manifest.
+- HMR with the `shakapacker-dev-server`, such as for hot-reloading React!
 - Automatic code splitting using multiple entry points to optimize JavaScript downloads.
 - [Webpack v5+](https://webpack.js.org/)
 - ES6 with [babel](https://babeljs.io/), [SWC](https://swc.rs/), or [Esbuild](https://github.com/privatenumber/esbuild-loader)
@@ -135,14 +136,14 @@ Add `shakapacker` gem to your `Gemfile`:
 bundle add shakapacker --strict
 ```
 
-Then running the following to install Webpacker:
+Then run the following to install Shakapacker:
 
 ```bash
 ./bin/bundle install
-./bin/rails webpacker:install
+./bin/rails shakapacker:install
 ```
 
-When `package.json` and/or `yarn.lock` changes, such as when pulling down changes to your local environment in a team settings, be sure to keep your NPM packages up-to-date:
+When `package.json` and/or `yarn.lock` changes, such as when pulling down changes to your local environment in team settings, be sure to keep your NPM packages up-to-date:
 
 ```bash
 yarn
@@ -156,32 +157,32 @@ yarn add @babel/core @babel/plugin-transform-runtime @babel/preset-env @babel/ru
   webpack webpack-assets-manifest webpack-cli webpack-merge webpack-sources webpack-dev-server
 ```
 
-Previously, these "webpack" and "babel" packages were direct dependencies for `webpacker`. By
+Previously, these "webpack" and "babel" packages were direct dependencies for `shakapacker`. By
 making these peer dependencies, you have control over the versions used in your webpack and babel configs.
 
 ### Note for Yarn v2 usage
 
 If you are using Yarn v2 (berry), please note that PnP modules are not supported.
 
-In order to use Shakapacker with Yarn v2, make sure you set `nodeLinker: node-modules` in your `.yarnrc.yml` file as per the [Yarn docs](https://yarnpkg.com/getting-started/migration#step-by-step) to opt out of Plug'n'Play behaviour.
+To use Shakapacker with Yarn v2, make sure you set `nodeLinker: node-modules` in your `.yarnrc.yml` file as per the [Yarn docs](https://yarnpkg.com/getting-started/migration#step-by-step) to opt out of Plug'n'Play behavior.
 
 ## Concepts
 
-At it's core, Shakapacker's essential functionality is to:
+At its core, Shakapacker's essential function is to:
 
 1. Provide configuration by a single file used by both Rails view helpers and JavaScript webpack compilation code.
-2. Provide Rails view helpers, utilizing this configuration file, so that a webpage can load JavaScript, CSS, and other static assets compiled by webpack, supporting bundle splitting, fingerprinting, and HMR.
-3. Provide a community supported, default webpack compilation that generates the necessary bundles and manifest, using the same configuration file. This compilation can be extended for any needs.
+2. Provide Rails view helpers, utilizing this configuration file so that a webpage can load JavaScript, CSS, and other static assets compiled by webpack, supporting bundle splitting, fingerprinting, and HMR.
+3. Provide a community-supported, default webpack compilation that generates the necessary bundles and manifest, using the same configuration file. This compilation can be extended for any needs.
 
 ## Usage
 
 ### Configuration and Code
 
-You will need your file system to correspond to the setup of your `webpacker.yml` file.
+You will need your file system to correspond to the setup of your `config/shakapacker.yml` file.
 
 Suppose you have the following configuration:
 
-`webpacker.yml`
+`shakapacker.yml`
 ```yml
 default: &default
   source_path: app/javascript
@@ -212,16 +213,20 @@ Webpack intelligently includes only necessary files. In this example, the file `
 
 `nested_entries` allows you to have webpack entry points nested in subdirectories. This defaults to false so you don't accidentally create entry points for an entire tree of files. In other words, with `nested_entries: false`, you can have your entire `source_path` used for your source (using the `source_entry_path: /`) and you place files at the top level that you want as entry points. `nested_entries: true` allows you to have entries that are in subdirectories. This is useful if you have entries that are generated, so you can have a `generated` subdirectory and easily separate generated files from the rest of your codebase.
 
+#### Setting custom config path
+
+You can use the environment variable `SHAKAPACKER_CONFIG` to enforce a particular path to the config file rather than the default `config/shakapacker.yml`.
+
 ### View Helpers
 The Shakapacker view helpers generate the script and link tags to get the webpack output onto your views.
 
-Be sure to consult the API documentation in the source code of [helper.rb](./lib/webpacker/helper.rb).
+Be sure to consult the API documentation in the source code of [helper.rb](./lib/shakapacker/helper.rb).
 
 **Note:** In order for your styles or static assets files to be available in your view, you would need to link them in your "pack" or entry file. Otherwise, Webpack won't know to package up those files.
 
 #### View Helpers `javascript_pack_tag` and `stylesheet_pack_tag`
 
-These view helpers take your `webpacker.yml` configuration file, along with the resulting webpack compilation `manifest.json` and generates the HTML to load the assets.
+These view helpers take your `shakapacker.yml` configuration file and the resulting webpack compilation `manifest.json` and generate the HTML to load the assets.
 
 You can then link the JavaScript pack in Rails views using the `javascript_pack_tag` helper. If you have styles imported in your pack file, you can link them by using `stylesheet_pack_tag`:
 
@@ -231,7 +236,7 @@ You can then link the JavaScript pack in Rails views using the `javascript_pack_
 ```
 
 The `javascript_pack_tag` and `stylesheet_pack_tag` helpers will include all the transpiled
-packs with the chunks in your view, which creates html tags for all the chunks.
+packs with the chunks in your view, which creates HTML tags for all the chunks.
 
 You can provide multiple packs and other attributes. Note, `defer` defaults to showing.
 
@@ -239,7 +244,7 @@ You can provide multiple packs and other attributes. Note, `defer` defaults to s
 <%= javascript_pack_tag 'calendar', 'map', 'data-turbo-track': 'reload' %>
 ```
 
-The resulting HTML would look like:
+The resulting HTML would look like this:
 ```
 <script src="/packs/vendor-16838bab065ae1e314.js" data-turbo-track="reload" defer></script>
 <script src="/packs/calendar~runtime-16838bab065ae1e314.js" data-turbo-track="reload" defer></script>
@@ -248,7 +253,7 @@ The resulting HTML would look like:
 <script src="/packs/map-16838bab065ae1e314.js" data-turbo-track="reload" defer></script>
 ```
 
-In this output, both the calendar and map codes might refer to other common libraries. Those get placed something like the vendor bundle. The view helper removes any duplication.
+In this output, both the calendar and map codes might refer to other common libraries. Those get placed in something like the vendor bundle. The view helper removes any duplication.
 
 Note, the default of "defer" for the `javascript_pack_tag`. You can override that to `false`. If you expose jquery globally with `expose-loader,` by using `import $ from "expose-loader?exposes=$,jQuery!jquery"` in your `app/javascript/application.js`, pass the option `defer: false` to your `javascript_pack_tag`.
 
@@ -271,7 +276,7 @@ While this also generally applies to `stylesheet_pack_tag`, you may use multiple
 
 #### View Helper `append_javascript_pack_tag`, `prepend_javascript_pack_tag` and `append_stylesheet_pack_tag`
 
-If you need configure your script pack names or stylesheet pack names from the view for a route or partials, then you will need some logic to ensure you call the helpers only once with multiple arguments. The new view helpers, `append_javascript_pack_tag` and `append_stylesheet_pack_tag` can solve this problem. The helper `append_javascript_pack_tag` will queue up script packs when the `javascript_pack_tag` is finally used. Similarly,`append_stylesheet_pack_tag` will queue up style packs when the `stylesheet_pack_tag` is finally used.
+If you need to configure your script pack names or stylesheet pack names from the view for a route or partials, then you will need some logic to ensure you call the helpers only once with multiple arguments. The new view helpers, `append_javascript_pack_tag` and `append_stylesheet_pack_tag` can solve this problem. The helper `append_javascript_pack_tag` will queue up script packs when the `javascript_pack_tag` is finally used. Similarly,`append_stylesheet_pack_tag` will queue up style packs when the `stylesheet_pack_tag` is finally used.
 
 Main view:
 ```erb
@@ -339,7 +344,7 @@ is the same as using this in the main layout:
 <%= javascript_pack_tag 'main', 'calendar', 'map', application' %>
 ```
 
-For alternative options of setting the additional packs, [see this discussion](https://github.com/shakacode/shakapacker/issues/39).
+For alternative options for setting the additional packs, [see this discussion](https://github.com/shakacode/shakapacker/issues/39).
 
 #### View Helper: `asset_pack_path`
 
@@ -380,17 +385,17 @@ If you want to use images in your stylesheets:
 
 ### Server-Side Rendering (SSR)
 
-Note, if you are using server-side rendering of JavaScript with dynamic code-splitting, as is often done with extensions to Webpacker, like [React on Rails](https://github.com/shakacode/react_on_rails), your JavaScript should create the link prefetch HTML tags that you will use, so you won't need to use to `asset_pack_path` in those circumstances.
+Note, if you are using server-side rendering of JavaScript with dynamic code-splitting, as is often done with extensions to Shakapacker, like [React on Rails](https://github.com/shakacode/react_on_rails), your JavaScript should create the link prefetch HTML tags that you will use, so you won't need to use to `asset_pack_path` in those circumstances.
 
 ### Development
 
-Webpacker ships with two binstubs: `./bin/webpacker` and `./bin/webpacker-dev-server`. Both are thin wrappers around the standard `webpack.js` and `webpack-dev-server.js` executables to ensure that the right configuration files and environmental variables are loaded based on your environment.
+Shakapacker ships with two binstubs: `./bin/shakapacker` and `./bin/shakapacker-dev-server`. Both are thin wrappers around the standard `webpack.js` and `webpack-dev-server.js` executables to ensure that the right configuration files and environmental variables are loaded based on your environment.
 
 _Note: older Shakapacker installations had set a missing NODE_ENV in the binstubs. Please remove this for versions 6.5.2 and newer._
 
 #### Automatic Webpack Code Building
 
-Shakapacker can be configured to automatically compile on demand when needed using the `webpacker.yml` `compile` option. This happens when you refer to any of the pack assets using the Shakapacker helper methods. This means that you don't have to run any separate processes. Compilation errors are logged to the standard Rails log. However, this auto-compilation happens when a web request is made that requires an updated webpack build, not when files change. Thus, that can be **painfully slow** for front-end development in this default way. Instead, you should either run the `bin/webpacker --watch` or run `./bin/webpacker-dev-server` during development.
+Shakapacker can be configured to automatically compile on demand when needed using `compile` option in the `shakapacker.yml`. This happens when you refer to any of the pack assets using the Shakapacker helper methods. This means that you don't have to run any separate processes. Compilation errors are logged to the standard Rails log. However, this auto-compilation happens when a web request is made that requires an updated webpack build, not when files change. Thus, that can be **painfully slow** for front-end development in this default way. Instead, you should either run the `bin/shakapacker --watch` or run `./bin/shakapacker-dev-server` during development.
 
 The `compile: true` option can be more useful for test and production builds.
 
@@ -399,43 +404,43 @@ The `compile: true` option can be more useful for test and production builds.
 Shakapacker ships with two different strategies that are used to determine whether assets need recompilation per the `compile: true` option:
 
 - `digest` - This strategy calculates SHA1 digest of files in your watched paths (see below). The calculated digest is then stored in a temp file. To check whether the assets need to be recompiled, Shakapacker calculates the SHA1 of the watched files and compares it with the one stored. If the digests are equal, no recompilation occurs. If the digests are different or the temp file is missing, files are recompiled.
-- `mtime` - This strategy looks at last modified at timestamps of both files AND directories in your watched paths. The timestamp of the most recent file or directory is then compared with the timestamp of `manifest.json` file generated. If the manifest file timestamp is newer than one of the most recently modified file or directory in the watched paths, no recompilation occurs. If the manifest file is order, files are recompiled.
+- `mtime` - This strategy looks at the last "modified at" timestamps of both files AND directories in your watched paths. The timestamp of the most recent file or directory is then compared with the timestamp of `manifest.json` file generated. If the manifest file timestamp is newer than one of the most recently modified files or directories in the watched paths, no recompilation occurs. If the manifest file is older, files are recompiled.
 
 The `mtime` strategy is generally faster than the `digest` one, but it requires stable timestamps, this makes it perfect for a development environment, such as needing to rebuild bundles for tests, or if you're not changing frontend assets much.
 
 In production or CI environments, the `digest` strategy is more suitable, unless you are using incremental builds or caching and can guarantee that the timestamps will not change after e.g. cache restore. However, many production or CI environments will explicitly compile assets, so `compile: false` is more appropriate. Otherwise, you'll waste time either checking file timestamps or computing digests.
 
-You can control what strategy is used by `compiler_strategy` option in `webpacker.yml` config file. By default `mtime` strategy is used in development environment, `digest` is used elsewhere.
+You can control what strategy is used by the `compiler_strategy` option in `shakapacker.yml` config file. By default `mtime` strategy is used in development environment, `digest` is used elsewhere.
 
-**Note:** If you are not using the webpack-dev-server, your packs will be served by Rails public file server. If you've enabled caching (Rails application `config.action_controller.perform_caching` setting), your changes will likely not be picked up due to `Cache-Control` header being set and assets being cached in browser memory. For more details see the [issue #88](https://github.com/shakacode/shakapacker/issues/88).
+**Note:** If you are not using the `shakapacker-dev-server`, your packs will be served by the Rails public file server. If you've enabled caching (Rails application `config.action_controller.perform_caching` setting), your changes will likely not be picked up due to `Cache-Control` header being set and assets being cached in the browser memory. For more details see [issue](https://github.com/shakacode/shakapacker/issues/88)[ #88](https://github.com/shakacode/shakapacker/issues/88)](https://github.com/shakacode/shakapacker/issues/88).
 
-If you want to use live code reloading, or you have enough JavaScript that on-demand compilation is too slow, you'll need to run `./bin/webpacker-dev-server`. This process will watch for changes in the relevant files, defined by `webpacker.yml` configuration settings for `source_path`, `source_entry_path`, and `additional_paths`, and it will then automatically reload the browser to match. This feature is also known as [Hot Module Replacement](https://webpack.js.org/concepts/hot-module-replacement/).
+If you want to use live code reloading, or you have enough JavaScript that on-demand compilation is too slow, you'll need to run `./bin/shakapacker-dev-server`. This process will watch for changes in the relevant files, defined by `shakapacker.yml` configuration settings for `source_path`, `source_entry_path`, and `additional_paths`, and it will then automatically reload the browser to match. This feature is also known as [Hot Module Replacement](https://webpack.js.org/concepts/hot-module-replacement/).
 
 #### Common Development Commands
 
 ```bash
 # webpack dev server
-./bin/webpacker-dev-server
+./bin/shakapacker-dev-server
 
 # watcher
-./bin/webpacker --watch --progress
+./bin/shakapacker --watch --progress
 
 # standalone build
-./bin/webpacker --progress
+./bin/shakapacker --progress
 ```
 
-Once you start this webpack development server, Webpacker will automatically start proxying all webpack asset requests to this server. When you stop this server, Rails will detect that it's not running and Rails will revert back to on-demand compilation _if_ you have the `compile` option set to true in your `config/webpacker.yml`
+Once you start this webpack development server, Shakapacker will automatically start proxying all webpack asset requests to this server. When you stop this server, Rails will detect that it's not running and Rails will revert back to on-demand compilation _if_ you have the `compile` option set to true in your `config/shakapacker.yml`
 
-You can use environment variables as options supported by [webpack-dev-server](https://webpack.js.org/configuration/dev-server/) in the form `WEBPACKER_DEV_SERVER_<OPTION>`. Please note that these environmental variables will always take precedence over the ones already set in the configuration file, and that the _same_ environmental variables must be available to the `rails server` process.
+You can use environment variables as options supported by [webpack-dev-server](https://webpack.js.org/configuration/dev-server/) in the form `SHAKAPACKER_DEV_SERVER_<OPTION>`. Please note that these environmental variables will always take precedence over the ones already set in the configuration file, and that the _same_ environmental variables must be available to the `rails server` process.
 
 ```bash
-WEBPACKER_DEV_SERVER_PORT=4305 WEBPACKER_DEV_SERVER_HOST=example.com WEBPACKER_DEV_SERVER_INLINE=true WEBPACKER_DEV_SERVER_HOT=false ./bin/webpacker-dev-server
+SHAKAPACKER_DEV_SERVER_PORT=4305 SHAKAPACKER_DEV_SERVER_HOST=example.com SHAKAPACKER_DEV_SERVER_INLINE=true SHAKAPACKER_DEV_SERVER_HOT=false ./bin/shakapacker-dev-server
 ```
 
-By default, the webpack dev server listens on `localhost:3035` in development for security purposes. However, if you want your app to be available on port 4035 over local LAN IP or a VM instance like vagrant, you can set the `port` and `host` when running `./bin/webpacker-dev-server` binstub:
+By default, the webpack dev server listens on `localhost:3035` in development for security purposes. However, if you want your app to be available on port 4035 over local LAN IP or a VM instance like vagrant, you can set the `port` and `host` when running `./bin/shakapacker-dev-server` binstub:
 
 ```bash
-WEBPACKER_DEV_SERVER_PORT=4305 WEBPACKER_DEV_SERVER_HOST=0.0.0.0 ./bin/webpacker-dev-server
+SHAKAPACKER_DEV_SERVER_PORT=4305 SHAKAPACKER_DEV_SERVER_HOST=0.0.0.0 ./bin/shakapacker-dev-server
 ```
 
 **Note:** You need to allow webpack-dev-server host as an allowed origin for `connect-src` if you are running your application in a restrict CSP environment (like Rails 5.2+). This can be done in Rails 5.2+ in the CSP initializer `config/initializers/content_security_policy.rb` with a snippet like this:
@@ -451,10 +456,10 @@ end
 
 ### Webpack Configuration
 
-First, you don't _need_ to use Shakapacker's webpack configuration. However, the `shakapacker` NPM package provides convenient access to configuration code that reads the `config/webpacker.yml` file which the view helpers also use. If you have your own customized webpack configuration, at the minimum, you must ensure:
+First, you don't _need_ to use Shakapacker's webpack configuration. However, the `shakapacker` NPM package provides convenient access to configuration code that reads the `config/shakapacker.yml` file which the view helpers also use. If you have your customized webpack configuration, at the minimum, you must ensure:
 
-1. Your output files go the right directory
-2. Your output includes a manifest, via package [`webpack-assets-manifest`](https://github.com/webdeveric/webpack-assets-manifest) that maps output names (your 'packs') to the fingerprinted versions, including bundle-splitting dependencies. That's the main secret sauce of webpacker!
+1. Your output files go to the right directory
+2. Your output includes a manifest, via package [`webpack-assets-manifest`](https://github.com/webdeveric/webpack-assets-manifest) that maps output names (your 'packs') to the fingerprinted versions, including bundle-splitting dependencies. That's the main secret sauce of Shakapacker!
 
 The most practical webpack configuration is to take the default from Shakapacker and then use [webpack-merge](https://github.com/survivejs/webpack-merge) to merge your customizations with the default. For example, suppose you want to add some `resolve.extensions`:
 
@@ -520,7 +525,7 @@ console.log(webpackConfig.source_path)
 console.log(JSON.stringify(webpackConfig, undefined, 2))
 ```
 
-You may want to modify rules in the default configuration. For instance, if you are using a custom svg loader, you may want to remove `.svg` from the default file loader rules. You can search and filter the default rules like so:
+You may want to modify the rules in the default configuration. For instance, if you are using a custom svg loader, you may want to remove `.svg` from the default file loader rules. You can search and filter the default rules like so:
 
 ```js
 const svgRule = config.module.rules.find(rule => rule.test.test('.svg'));
@@ -538,7 +543,7 @@ By default, you will find the Shakapacker preset in your `package.json`. Note, y
   ]
 },
 ```
-Optionally, you can change your Babel configuration by removing these lines in your `package.json` and add [a Babel configuration file](https://babeljs.io/docs/en/config-files) in your project. For an example customization based on the original, see [Customizing Babel Config](./docs/customizing_babel_config.md).
+Optionally, you can change your Babel configuration by removing these lines in your `package.json` and adding [a Babel](https://babeljs.io/docs/en/config-files) configuration file](https://babeljs.io/docs/en/config-files) to your project. For an example of customization based on the original, see [Customizing Babel Config](./docs/customizing_babel_config.md).
 
 
 ### SWC configuration
@@ -610,7 +615,7 @@ module.exports = merge(webpackConfig, {
 
 #### CSS
 
-To enable CSS support in your application, add following packages:
+To enable CSS support in your application, add the following packages:
 
 ```bash
 yarn add css-loader style-loader mini-css-extract-plugin css-minimizer-webpack-plugin
@@ -670,7 +675,7 @@ yarn add coffeescript coffee-loader
 
 #### Other frameworks
 
-Please follow webpack integration guide for relevant framework or library,
+Please follow webpack integration guide for the relevant framework or library,
 
 1. [Svelte](https://github.com/sveltejs/svelte-loader#install)
 2. [Angular](https://v2.angular.io/docs/ts/latest/guide/webpack.html#!#configure-webpack)
@@ -707,9 +712,9 @@ module.exports = merge(vueConfig, webpackConfig)
 
 ### Custom Rails environments
 
-Out of the box Shakapacker ships with - development, test and production environments in `config/webpacker.yml` however, in most production apps extra environments are needed as part of deployment workflow. Shakapacker supports this out of the box from version 3.4.0+ onwards.
+Out of the box Shakapacker ships with - development, test and production environments in `config/shakapacker.yml` however, in most production apps extra environments are needed as part of the deployment workflow. Shakapacker supports this out of the box from version 3.4.0+ onwards.
 
-You can choose to define additional environment configurations in webpacker.yml,
+You can choose to define additional environment configurations in shakapacker.yml,
 
 ```yml
 staging:
@@ -725,15 +730,15 @@ staging:
   public_output_path: packs-staging
 ```
 
-Otherwise Shakapacker will use production environment as a fallback environment for loading configurations. Please note, `NODE_ENV` can either be set to `production`, `development` or `test`. This means you don't need to create additional environment files inside `config/webpacker/*` and instead use webpacker.yml to load different configurations using `RAILS_ENV`.
+Otherwise, Shakapacker will use the production environment as a fallback environment for loading configurations. Please note, `NODE_ENV` can either be set to `production`, `development` or `test`. This means you don't need to create additional environment files inside `config/shakapacker/*` and instead use shakapacker.yml to load different configurations using `RAILS_ENV`.
 
-For example, the below command will compile assets in production mode but will use staging configurations from `config/webpacker.yml` if available or use fallback production environment configuration:
+For example, the below command will compile assets in production mode but will use staging configurations from `config/shakapacker.yml` if available or use fallback production environment configuration:
 
 ```bash
 RAILS_ENV=staging bundle exec rails assets:precompile
 ```
 
-And, this will compile in development mode and load configuration for cucumber environment if defined in webpacker.yml or fallback to production configuration
+And, this will compile in development mode and load configuration for the cucumber environment if defined in `shakapacker.yml` or fallback to production configuration
 
 ```bash
 RAILS_ENV=cucumber NODE_ENV=development bundle exec rails assets:precompile
@@ -743,24 +748,24 @@ Please note, binstubs compiles in development mode however rake tasks compiles i
 
 ```bash
 # Compiles in development mode unless NODE_ENV is specified, per the binstub source
-./bin/webpacker
-./bin/webpacker-dev-server
+./bin/shakapacker
+./bin/shakapacker-dev-server
 
-# Compiles in production mode by default unless NODE_ENV is specified, per `lib/tasks/webpacker/compile.rake`
+# Compiles in production mode by default unless NODE_ENV is specified, per `lib/tasks/shakapacker/compile.rake`
 bundle exec rails assets:precompile
-bundle exec rails webpacker:compile
+bundle exec rails shakapacker:compile
 ```
 
 ### Upgrading
 
-You can run following commands to upgrade Shakapacker to the latest stable version. This process involves upgrading the gem and related JavaScript packages:
+You can run the following commands to upgrade Shakapacker to the latest stable version. This process involves upgrading the gem and related JavaScript packages:
 
 ```bash
 # check your Gemfile for version restrictions
 bundle update shakapacker
 
 # overwrite your changes to the default install files and revert any unwanted changes from the install
-rails webpacker:install
+rails shakapacker:install
 
 # yarn 1 instructions
 yarn upgrade shakapacker --latest
@@ -778,22 +783,22 @@ Also, consult the [CHANGELOG](./CHANGELOG.md) for additional upgrade links.
 
 ### Paths
 
-By default, Shakapacker ships with simple conventions for where the JavaScript app files and compiled webpack bundles will go in your Rails app. All these options are configurable from `config/webpacker.yml` file.
+By default, Shakapacker ships with simple conventions for where the JavaScript app files and compiled webpack bundles will go in your Rails app. All these options are configurable from `config/shakapacker.yml` file.
 
-The configuration for what webpack is supposed to compile by default rests on the convention that every file in `app/javascript/`**(default)** or whatever path you set for `source_entry_path` in the `webpacker.yml` configuration is turned into their own output files (or entry points, as webpack calls it). Therefore you don't want to put any file inside `app/javascript` directory that you do not want to be an entry file. As a rule of thumb, put all files you want to link in your views inside "app/javascript/" directory and keep everything else under subdirectories like `app/javascript/controllers`.
+The configuration for what webpack is supposed to compile by default rests on the convention that every file in `app/javascript/`**(default)** or whatever path you set for `source_entry_path` in the `shakapacker.yml` configuration is turned into their own output files (or entry points, as webpack calls it). Therefore you don't want to put any file inside `app/javascript` directory that you do not want to be an entry file. As a rule of thumb, put all files you want to link in your views inside "app/javascript/" directory and keep everything else under subdirectories like `app/javascript/controllers`.
 
 Suppose you want to change the source directory from `app/javascript` to `frontend` and output to `assets/packs`. This is how you would do it:
 
 ```yml
-# config/webpacker.yml
+# config/shakapacker.yml
 source_path: frontend # packs are the files in frontend/
 public_output_path: assets/packs # outputs to => public/assets/packs
 ```
 
-Similarly you can also control and configure `webpack-dev-server` settings from `config/webpacker.yml` file:
+Similarly, you can also control and configure `webpack-dev-server` settings from `config/shakapacker.yml` file:
 
 ```yml
-# config/webpacker.yml
+# config/shakapacker.yml
 development:
   dev_server:
     host: localhost
@@ -806,7 +811,7 @@ If you want to have HMR and separate link tags, set `hmr: true` and `inline_css:
 
 ### Additional paths
 
-If you are adding Shakapacker to an existing app that has most of the assets inside `app/assets` or inside an engine, and you want to share that with webpack modules, you can use the `additional_paths` option available in `config/webpacker.yml`. This lets you
+If you are adding Shakapacker to an existing app that has most of the assets inside `app/assets` or inside an engine, and you want to share that with webpack modules, you can use the `additional_paths` option available in `config/shakapacker.yml`. This lets you
 add additional paths that webpack should look up when resolving modules:
 
 ```yml
@@ -821,20 +826,20 @@ import 'stylesheets/main'
 import 'images/rails.png'
 ```
 
-**Note:** Please be careful when adding paths here otherwise it will make the compilation slow, consider adding specific paths instead of whole parent directory if you just need to reference one or two modules
+**Note:** Please be careful when adding paths here otherwise it will make the compilation slow, consider adding specific paths instead of the whole parent directory if you just need to reference one or two modules
 
-**Also note:** While importing assets living outside your `source_path` defined in webpacker.yml (like, for instance, assets under `app/assets`) from within your packs using _relative_ paths like `import '../../assets/javascripts/file.js'` will work in development, Shakapacker won't recompile the bundle in production unless a file that lives in one of it's watched paths has changed (check out `Webpacker::MtimeStrategy#latest_modified_timestamp` or `Webpacker::DigestStrategy#watched_files_digest` depending on strategy configured by `compiler_strategy` option in `webpacker.yml`). That's why you'd need to add `app/assets` to the additional_paths as stated above and use `import 'javascripts/file.js'` instead.
+**Also note:** While importing assets living outside your `source_path` defined in shakapacker.yml (like, for instance, assets under `app/assets`) from within your packs using _relative_ paths like `import '../../assets/javascripts/file.js'` will work in development, Shakapacker won't recompile the bundle in production unless a file that lives in one of it's watched paths has changed (check out `Shakapacker::MtimeStrategy#latest_modified_timestamp` or `Shakapacker::DigestStrategy#watched_files_digest` depending on strategy configured by `compiler_strategy` option in `shakapacker.yml`). That's why you'd need to add `app/assets` to the additional_paths as stated above and use `import 'javascripts/file.js'` instead.
 
 
 ## Deployment
 
-Shakapacker hooks up a new `webpacker:compile` task to `assets:precompile`, which gets run whenever you run `assets:precompile`. If you are not using Sprockets, `webpacker:compile` is automatically aliased to `assets:precompile`. Similar to sprockets both rake tasks will compile packs in production mode but will use `RAILS_ENV` to load configuration from `config/webpacker.yml` (if available).
+Shakapacker hooks up a new `shakapacker:compile` task to `assets:precompile`, which gets run whenever you run `assets:precompile`. If you are not using Sprockets, `shakapacker:compile` is automatically aliased to `assets:precompile`. Similar to sprockets both rake tasks will compile packs in production mode but will use `RAILS_ENV` to load configuration from `config/shakapacker.yml` (if available).
 
-This behavior is optional & can be disabled by either setting an `WEBPACKER_PRECOMPILE` environment variable to `false`, `no`, `n`, or `f`, or by setting a `webpacker_precompile` key in your `webpacker.yml` to `false`. ([source code](./lib/webpacker/configuration.rb#L30))
+This behavior is optional & can be disabled by either setting a `SHAKAPACKER_PRECOMPILE` environment variable to `false`, `no`, `n`, or `f`, or by setting a `shakapacker_precompile` key in your `shakapacker.yml` to `false`. ([source code](./lib/shakapacker/configuration.rb#L34))
 
 When compiling assets for production on a remote server, such as a continuous integration environment, it's recommended to use `yarn install --frozen-lockfile` to install NPM packages on the remote host to ensure that the installed packages match the `yarn.lock` file.
 
-If you are using a CDN setup, webpacker will use the configured [asset host](https://guides.rubyonrails.org/configuring.html#rails-general-configuration) value to prefix URLs for images or font icons which are included inside JS code or CSS. It is possible to override this value during asset compilation by setting the `WEBPACKER_ASSET_HOST` environment variable.
+If you are using a CDN setup, Shakapacker will use the configured [asset host](https://guides.rubyonrails.org/configuring.html#rails-general-configuration) value to prefix URLs for images or font icons which are included inside JS code or CSS. It is possible to override this value during asset compilation by setting the `SHAKAPACKER_ASSET_HOST` environment variable.
 
 ## Example Apps
 * [React on Rails Tutorial With SSR, HMR fast refresh, and TypeScript](https://github.com/shakacode/react_on_rails_tutorial_with_ssr_and_hmr_fast_refresh)
@@ -846,14 +851,19 @@ See the doc page for [Troubleshooting](./docs/troubleshooting.md).
 
 ## Contributing
 
-We encourage you to contribute to Shakapacker/Webpacker! See [CONTRIBUTING](CONTRIBUTING.md) for guidelines about how to proceed. We have a [Slack discussion channel](https://reactrails.slack.com/join/shared_invite/enQtNjY3NTczMjczNzYxLTlmYjdiZmY3MTVlMzU2YWE0OWM0MzNiZDI0MzdkZGFiZTFkYTFkOGVjODBmOWEyYWQ3MzA2NGE1YWJjNmVlMGE).
+We encourage you to contribute to Shakapacker! See [CONTRIBUTING](CONTRIBUTING.md) for guidelines about how to proceed. We have a [Slack discussion channel](https://reactrails.slack.com/join/shared_invite/enQtNjY3NTczMjczNzYxLTlmYjdiZmY3MTVlMzU2YWE0OWM0MzNiZDI0MzdkZGFiZTFkYTFkOGVjODBmOWEyYWQ3MzA2NGE1YWJjNmVlMGE).
 
 ## License
 
-Webpacker is released under the [MIT License](https://opensource.org/licenses/MIT).
+Shakapacker is released under the [MIT License](https://opensource.org/licenses/MIT).
   
 ## Supporters
 
+The following companies support our Open Source projects, and ShakaCode uses their products!
+
+<br />
+<br />
+
 <a href="https://www.jetbrains.com">
   <img src="https://user-images.githubusercontent.com/4244251/184881139-42e4076b-024b-4b30-8c60-c3cd0e758c0a.png" alt="JetBrains" height="120px">
 </a>
@@ -881,8 +891,3 @@ Webpacker is released under the [MIT License](https://opensource.org/licenses/MI
 <a href="https://reviewable.io">
   <img src="https://user-images.githubusercontent.com/20628911/230848305-c94510a4-82d7-468f-bf9f-eeb81d3f2ce0.png" alt="Reviewable" height="55px">
 </a>
-
-<br />
-<br />
-
-The following companies support our open source projects, and ShakaCode uses their products!
diff --git a/Rakefile b/Rakefile
index db481e368..d19721ccc 100644
--- a/Rakefile
+++ b/Rakefile
@@ -8,3 +8,8 @@ rescue LoadError
 end
 
 task default: :test
+
+desc "Run backward compatibility specs"
+task :test_bc do
+  system("bundle exec rspec spec/backward_compatibility_specs/*_spec_bc.rb")
+end
diff --git a/config/shakapacker.yml b/config/shakapacker.yml
new file mode 120000
index 000000000..f0faf733f
--- /dev/null
+++ b/config/shakapacker.yml
@@ -0,0 +1 @@
+../lib/install/config/shakapacker.yml
\ No newline at end of file
diff --git a/config/webpacker.yml b/config/webpacker.yml
deleted file mode 120000
index cba4bfb4f..000000000
--- a/config/webpacker.yml
+++ /dev/null
@@ -1 +0,0 @@
-../lib/install/config/webpacker.yml
\ No newline at end of file
diff --git a/docs/deployment.md b/docs/deployment.md
index 0524d6449..1fe0f6f66 100644
--- a/docs/deployment.md
+++ b/docs/deployment.md
@@ -1,16 +1,16 @@
 # Deployment
 
-Webpacker hooks up a new `webpacker:compile` task to `assets:precompile`, which gets run whenever you run `assets:precompile`.
-If you are not using Sprockets `webpacker:compile` is automatically aliased to `assets:precompile`.
+Shakapacker hooks up a new `shakapacker:compile` task to `assets:precompile`, which gets run whenever you run `assets:precompile`.
+If you are not using Sprockets `shakapacker:compile` is automatically aliased to `assets:precompile`.
 
 ```
 
 ## Heroku
 
-In order for your Webpacker app to run on Heroku, you'll need to do a bit of configuration before hand.
+In order for your Shakapacker app to run on Heroku, you'll need to do a bit of configuration before hand.
 
 ```bash
-heroku create my-webpacker-heroku-app
+heroku create my-shakapacker-heroku-app
 heroku addons:create heroku-postgresql:hobby-dev
 heroku buildpacks:add heroku/nodejs
 heroku buildpacks:add heroku/ruby
@@ -28,11 +28,11 @@ Your production build process is responsible for running `yarn install` before `
 
 ## Nginx
 
-Webpacker doesn't serve anything in production. You’re expected to configure your web server to serve files in public/ directly.
+Shakapacker doesn't serve anything in production. You’re expected to configure your web server to serve files in public/ directly.
 
 Some servers support sending precompressed versions of files when they're available. For example, nginx offers a `gzip_static` directive that serves files with the `.gz` extension to supported clients. With an optional module, nginx can also serve Brotli compressed files with the `.br` extension (see below for installation and configuration instructions).
 
-Here's a sample nginx site config for a Rails app using Webpacker:
+Here's a sample nginx site config for a Rails app using Shakapacker:
 
 ```nginx
 upstream app {
@@ -88,17 +88,17 @@ Now, you can set `brotli_static on;` in your nginx site config, as per the confi
 
 ## CDN
 
-Webpacker out-of-the-box provides CDN support using your Rails app `config.action_controller.asset_host` setting. If you already have [CDN](http://guides.rubyonrails.org/asset_pipeline.html#cdns) added in your Rails app
-you don't need to do anything extra for Webpacker, it just works.
+Shakapacker out-of-the-box provides CDN support using your Rails app `config.action_controller.asset_host` setting. If you already have [CDN](http://guides.rubyonrails.org/asset_pipeline.html#cdns) added in your Rails app
+you don't need to do anything extra for Shakapacker, it just works.
 
 ## Capistrano
 
 ### Assets compiling on every deployment even if JavaScript and CSS files are not changed
 
-Make sure you have your public outputh path (default `public/packs`), the webpacker cache path (default `tmp/webpacker`) and `node_modules` in `:linked_dirs`
+Make sure you have your public outputh path (default `public/packs`), the shakapacker cache path (default `tmp/shakapacker`) and `node_modules` in `:linked_dirs`
 
 ```ruby
-append :linked_dirs, "log", "tmp/pids", "tmp/cache", "tmp/sockets", "tmp/webpacker", "public/packs", ".bundle", "node_modules"
+append :linked_dirs, "log", "tmp/pids", "tmp/cache", "tmp/sockets", "tmp/shakapacker", "public/packs", ".bundle", "node_modules"
 ```
 
 If you have `node_modules` added to `:linked_dirs` you'll need to run yarn install before `deploy:assets:precompile`, so you can add this code snippet at the bottom deploy.rb
diff --git a/docs/developing_webpacker.md b/docs/developing_webpacker.md
index 53557160c..4728fe498 100644
--- a/docs/developing_webpacker.md
+++ b/docs/developing_webpacker.md
@@ -1,4 +1,4 @@
-# Developing Webpacker
+# Developing Shakapacker
 
 It's a little trickier for Rails developers to work on the JS code of a project like shakacode/shakapacker. So here are some tips!
 
@@ -7,16 +7,16 @@ For example, for React on Rails Changes, I'm using [shakacode/react_on_rails_tut
 This directory is the `TEST_APP_DIR`.
 
 ## Fork shakacode/shakapacker
-Let's call the shakacode/shakapacker directory `WEBPACKER_DIR` which has shakacode/shakapacker's `package.json`.
+Let's call the shakacode/shakapacker directory `SHAKAPACKER_DIR` which has shakacode/shakapacker's `package.json`.
 
 ## Changing the Package
 ### Setup with Yalc
 Use [`yalc`](https://github.com/wclr/yalc) unless you like yak shaving weird errors.
-1. In `WEBPACKER_DIR`, run `yalc publish`
+1. In `SHAKAPACKER_DIR`, run `yalc publish`
 2. In `TEST_APP_DIR`, run `yalc link shakapacker`
 
 ## Update the Package Code
-1. Make some JS change in WEBPACKER_DIR
+1. Make some JS change in SHAKAPACKER_DIR
 2. Run `yalc push` and your changes will be pushed to your `TEST_APP_DIR`'s node_modules.
 3. You may need to run `yarn` in `TEST_APP_DIR` if you added or removed dependencies of shakacode/shakapacker.
 
@@ -25,5 +25,5 @@ Use [`yalc`](https://github.com/wclr/yalc) unless you like yak shaving weird err
 For the Ruby part, just change the gem reference `TEST_APP_DIR`, like:
 
 ```ruby
-gem "webpacker", path: "../../forks/webpacker"
+gem "shakapacker", path: "../../forks/shakapacker"
 ```
diff --git a/docs/react.md b/docs/react.md
index 61a939011..a56ef9f6c 100644
--- a/docs/react.md
+++ b/docs/react.md
@@ -47,7 +47,7 @@ With HMR enabled, Shakapacker will automatically update only that part of the pa
 
 To enable HMR in a React app, proceed as follows:.
 
-In `config/webpacker.yml` set `hmr` is set to `true`.
+In `config/shakapacker.yml` set `hmr` is set to `true`.
 
 Install the [react-refresh](https://www.npmjs.com/package/react-refresh) package, as well as [@pmmmwh/react-refresh-webpack-plugin](https://www.npmjs.com/package/@pmmmwh/react-refresh-webpack-plugin):
 
@@ -139,7 +139,7 @@ rails new myapp --skip-javascript
 cd myapp
 bundle add shakapacker --strict
 ./bin/bundle install
-./bin/rails webpacker:install
+./bin/rails shakapacker:install
 yarn add react react-dom @babel/preset-react
 yarn add css-loader style-loader mini-css-extract-plugin css-minimizer-webpack-plugin
 ```
@@ -182,7 +182,7 @@ export default HelloMessage;
 h1 { color: blue; }
 ```
 
-7. Enable HMR in config/webpacker.yml:
+7. Enable HMR in config/shakapacker.yml:
 ```shell
 hmr: true
 ```
@@ -261,7 +261,7 @@ module.exports = function (api) {
 9. Start the Rails server and the webpack-dev-server in separate console windows:
 ```shell
 rails s
-./bin/webpacker-dev-server
+./bin/shakapacker-dev-server
 ```
 
 10. Hit: <http://localhost:3000/site/index>
diff --git a/docs/style_loader_vs_mini_css.md b/docs/style_loader_vs_mini_css.md
index 295e7e56c..adb701b98 100644
--- a/docs/style_loader_vs_mini_css.md
+++ b/docs/style_loader_vs_mini_css.md
@@ -2,10 +2,10 @@
 
 You have two options for serving CSS in development:
 
-1. You can opt to serve CSS via style-loader (as was traditionally done in a Webpack setup), where CSS is written by Javascript served by Webpacker into a `<style>` tag, or
+1. You can opt to serve CSS via style-loader (as was traditionally done in a Webpack setup), where CSS is written by Javascript served by Shakapacker into a `<style>` tag, or
 2. You can opt to serve CSS as a full CSS file via mini-css-extract-plugin, which uses a standard `<link>` tag to load a fully separate CSS file.
 
-Both options support HMR. The default is style-loader. If you want to use mini-css-extract-plugin in development, set `inline_css: false` in the development dev_server section of your webpacker.yml:
+Both options support HMR. The default is style-loader. If you want to use mini-css-extract-plugin in development, set `inline_css: false` in the development dev_server section of your shakapacker.yml:
 
 ```yml
 development:
diff --git a/docs/troubleshooting.md b/docs/troubleshooting.md
index d81a9cad9..0d8a581f0 100644
--- a/docs/troubleshooting.md
+++ b/docs/troubleshooting.md
@@ -5,7 +5,7 @@
 1. Read the error message carefully. The error message will tell you the precise key value
    that is not matching what Webpack expects.
 
-2. Put a `debugger` statement in your Webpack configuration and run `bin/webpacker --debug-webpacker`.
+2. Put a `debugger` statement in your Webpack configuration and run `bin/shakapacker --debug-shakapacker`.
    If you have a node debugger installed, you'll see the Chrome debugger for your webpack
    config. For example, install the Chrome extension
    [NiM](https://chrome.google.com/webstore/detail/nodejs-v8-inspector-manag/gnhhdgbaldcilmgcpfddgdbkhjohddkj) and
@@ -13,9 +13,9 @@
    For more details on debugging, see the official
    [Webpack docs on debugging](https://webpack.js.org/contribute/debugging/#devtools)
 
-3. Any arguments that you add to bin/webpacker get sent to webpack. For example, you can pass `--debug` to switch loaders to debug mode. See [webpack CLI debug options](https://webpack.js.org/api/cli/#debug-options) for more information on the available options.
+3. Any arguments that you add to bin/shakapacker get sent to webpack. For example, you can pass `--debug` to switch loaders to debug mode. See [webpack CLI debug options](https://webpack.js.org/api/cli/#debug-options) for more information on the available options.
 
-4. You can also pass additional options to the command to run the webpack-dev-server and start the webpack-dev-server with the option `--debug-webpacker`
+4. You can also pass additional options to the command to run the webpack-dev-server and start the webpack-dev-server with the option `--debug-shakapacker`
 
 ## Incorrect peer dependencies
 The latest version of Shakapacker uses peer dependencies to make upgrading easier. However, there's a catch.
@@ -38,12 +38,12 @@ So, be sure to investigate warnings from `yarn install`!
 ## ENOENT: no such file or directory - node-sass
 
 If you get the error `ENOENT: no such file or directory - node-sass` on deploy with
-`assets:precompile` or `bundle exec rails webpacker:compile` you may need to
+`assets:precompile` or `bundle exec rails shakapacker:compile` you may need to
 move Sass to production `dependencies`.
 
 Move any packages that related to Sass (e.g. `node-sass` or `sass-loader`) from
 `devDependencies` to `dependencies` in `package.json`. This is because
-webpacker is running on a production system with the Rails workflow to build
+shakapacker is running on a production system with the Rails workflow to build
 the assets. Particularly on hosting providers that try to detect and do the right
 thing, like Heroku.
 
@@ -64,11 +64,11 @@ In `package.json`:
 
 * If you get this error `Can't find hello_react.js in manifest.json`
 when loading a view in the browser it's because webpack is still compiling packs.
-Webpacker uses a `manifest.json` file to keep track of packs in all environments,
+Shakapacker uses a `manifest.json` file to keep track of packs in all environments,
 however since this file is generated after packs are compiled by webpack. So,
 if you load a view in browser whilst webpack is compiling you will get this error.
 Therefore, make sure webpack
-(i.e `./bin/webpacker-dev-server`) is running and has
+(i.e `./bin/shakapacker-dev-server`) is running and has
 completed the compilation successfully before loading a view.
 
 
@@ -85,7 +85,7 @@ completed the compilation successfully before loading a view.
 
 ## webpack or webpack-dev-server not found
 
-* This could happen if `webpacker:install` step is skipped. Please run `bundle exec rails webpacker:install` to fix the issue.
+* This could happen if `shakapacker:install` step is skipped. Please run `bundle exec rails shakapacker:install` to fix the issue.
 
 * If you encounter the above error on heroku after upgrading from Rails 4.x to 5.1.x, then the problem might be related to missing `yarn` binstub. Please run following commands to update/add binstubs:
 
@@ -97,7 +97,7 @@ bundle config --delete bin
 ## Running webpack on Windows
 
 If you are running webpack on Windows, your command shell may not be able to interpret the preferred interpreter
-for the scripts generated in `bin/webpacker` and `bin/webpacker-dev-server`. Instead you'll want to run the scripts
+for the scripts generated in `bin/shakapacker` and `bin/shakapacker-dev-server`. Instead you'll want to run the scripts
 manually with Ruby:
 
 ```
@@ -107,7 +107,7 @@ C:\path>ruby bin\webpack-dev-server
 
 ## Invalid configuration object. webpack has been initialised using a configuration object that does not match the API schema.
 
-If you receive this error when running `$ ./bin/webpacker-dev-server` ensure your configuration is correct; most likely the path to your "packs" folder is incorrect if you modified from the original "source_path" defined in `config/webpacker.yml`.
+If you receive this error when running `$ ./bin/shakapacker-dev-server` ensure your configuration is correct; most likely the path to your "packs" folder is incorrect if you modified from the original "source_path" defined in `config/shakapacker.yml`.
 
 ## Running Elm on Continuous Integration (CI) services such as CircleCI, CodeShip, Travis CI
 
@@ -132,7 +132,7 @@ chmod +x $HOME/your_rails_app/node_modules/.bin/elm-make
 ```
 
 ## Rake assets:precompile fails. ExecJS::RuntimeError
-This error occurs because you are trying to minify by `terser` a pack that's already been minified by Webpacker. To avoid this conflict and prevent appearing of `ExecJS::RuntimeError` error, you will need to disable uglifier from Rails config:
+This error occurs because you are trying to minify by `terser` a pack that's already been minified by Shakapacker. To avoid this conflict and prevent appearing of `ExecJS::RuntimeError` error, you will need to disable uglifier from Rails config:
 
 ```ruby
 # In production.rb
@@ -164,10 +164,10 @@ module.exports = merge(webpackConfig, {
 
 ### Compilation Fails Silently
 
-If compiling is not producing output files and there are no error messages to help troubleshoot. Setting the `webpack_compile_output` configuration variable to `true` in webpacker.yml may add some helpful error information to your log file (Rails `log/development.log` or `log/production.log`)
+If compiling is not producing output files and there are no error messages to help troubleshoot. Setting the `webpack_compile_output` configuration variable to `true` in shakapacker.yml may add some helpful error information to your log file (Rails `log/development.log` or `log/production.log`)
 
 ```yml
-# webpacker.yml
+# shakapacker.yml
 default: &default
   source_path: app/javascript
   source_entry_path: packs
@@ -218,11 +218,11 @@ using Heroku's Pipeline promote feature). You might find that your production
 application is using your staging `config.asset_host` host when using
 `javascript_pack_tag`.
 
-This can be fixed by setting the environment variable `WEBPACKER_ASSET_HOST` to
+This can be fixed by setting the environment variable `SHAKAPACKER_ASSET_HOST` to
 an empty string where your assets are compiled. On Heroku this is done under
 *Settings* -> *Config Vars*.
 
-This way webpacker won't hard-code the CDN host into the manifest file used by
+This way shakapacker won't hard-code the CDN host into the manifest file used by
 `javascript_pack_tag`, but instead fetch the CDN host at runtime, resolving the
 issue.
 
diff --git a/docs/using_esbuild_loader.md b/docs/using_esbuild_loader.md
index bab426fa9..eaeee16d5 100644
--- a/docs/using_esbuild_loader.md
+++ b/docs/using_esbuild_loader.md
@@ -27,7 +27,7 @@ To use esbuild as your transpiler today. You need to do two things:
 yarn add esbuild esbuild-loader
 ```
 
-2. Add or change `webpacker_loader` value in your default `webpacker.yml` config to `esbuild`
+2. Add or change `shakapacker_loader` value in your default `shakapacker.yml` config to `esbuild`
 The default configuration of babel is done by using `package.json` to use the file within the `shakapacker` package.
 
 ```yml
@@ -36,7 +36,7 @@ default: &default
   source_entry_path: /
   public_root_path: public
   public_output_path: packs
-  cache_path: tmp/webpacker
+  cache_path: tmp/shakapacker
   webpack_compile_output: true
 
   # Additional paths webpack should look up modules
diff --git a/docs/using_swc_loader.md b/docs/using_swc_loader.md
index 63fc6f7bb..31109fd1d 100644
--- a/docs/using_swc_loader.md
+++ b/docs/using_swc_loader.md
@@ -22,7 +22,7 @@ In order to use SWC as your compiler today. You need to do two things:
 yarn add @swc/core swc-loader
 ```
 
-2. Add or change `webpack_loader` value in your default `webpacker.yml` config to `swc`
+2. Add or change `webpack_loader` value in your default `shakapacker.yml` config to `swc`
 The default configuration of babel is done by using `package.json` to use the file within the `shakapacker` package.
 
 ```yml
@@ -31,7 +31,7 @@ default: &default
   source_entry_path: /
   public_root_path: public
   public_output_path: packs
-  cache_path: tmp/webpacker
+  cache_path: tmp/shakapacker
   webpack_compile_output: true
 
   # Additional paths webpack should look up modules
diff --git a/docs/v7_upgrade.md b/docs/v7_upgrade.md
new file mode 100644
index 000000000..cfcf613b9
--- /dev/null
+++ b/docs/v7_upgrade.md
@@ -0,0 +1,28 @@
+# Upgrading from Shakapacker v6 to v7
+
+There will be several substantial and breaking changes in Shakapacker v7 that you need to manually account for when coming from Shakapacker v6.
+
+## Noticeable Changes
+
+### Usages of 'webpacker' should now be 'shakapacker'
+
+Shakapacker v6 kept the 'webpacker' spelling. As a result, many config filenames, environment variables, rake tasks, etc., used the 'webpacker' spelling. Shakapacker 7 requires renaming to the 'shakapacker' spelling.
+
+Shakapacker v7 provides a high degree of backward compatibility for spelling changes. It displays deprecation messages in the terminal to help the developers have a smooth experience in making the required transition to the new requirements.
+
+Please note that Shakapacker v8 will remove any backward compatibility for spelling.
+
+## Upgrade Steps
+
+**Note:** At each step of changing the version, ensure that you update both gem and npm versions to the same "exact" version (like `x.y.z` and not `^x.y.z` or `>= x.y.z`).
+
+1. Upgrade Shakapacker to the latest 6.x version and ensure no issues running your application. 
+2. Upgrade Shakapacker to version 7.
+3. Change spelling from Webpacker to Shakapacker
+    - Rename constant `Webpacker` to `Shakapacker`.
+    - Rename`Shakapacker.config.webpacker_precompile?` method, replace it with `Shakapacker.config.shakapacker_precompile?`
+    - Rename `config/shakapacker.yml` to `config/webpacker.yml`.
+    - Change `webpacker_precompile` entry to `shakapacker_precompile` if it exists in the config file.
+    - Run `rake shakapacker:binstubs` to get the new files in place and delete the old webpacker ones. Alternatively, if you have updated these files manually, rename `bin/webpacker` and `bin/webpacker-dev-server` to `bin/shakapacker` and `bin/shakapacker-dev-server`, and update the content of these files to change 'webpacker' to 'shakapacker'.
+    - `--debug-webpacker` is now `--debug-shakapacker` for your shakapacker binstubs.
+    - Rename environment variables from `WEBPACKER_XYZ` to `SHAKAPACKER_XYZ`.
diff --git a/lib/install/bin/shakapacker b/lib/install/bin/shakapacker
new file mode 100755
index 000000000..13a008dcf
--- /dev/null
+++ b/lib/install/bin/shakapacker
@@ -0,0 +1,13 @@
+#!/usr/bin/env ruby
+
+ENV["RAILS_ENV"] ||= "development"
+ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../../Gemfile", __FILE__)
+
+require "bundler/setup"
+require "shakapacker"
+require "shakapacker/webpack_runner"
+
+APP_ROOT = File.expand_path("..", __dir__)
+Dir.chdir(APP_ROOT) do
+  Shakapacker::WebpackRunner.run(ARGV)
+end
diff --git a/lib/install/bin/shakapacker-dev-server b/lib/install/bin/shakapacker-dev-server
new file mode 100755
index 000000000..5ae889798
--- /dev/null
+++ b/lib/install/bin/shakapacker-dev-server
@@ -0,0 +1,13 @@
+#!/usr/bin/env ruby
+
+ENV["RAILS_ENV"] ||= "development"
+ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../../Gemfile", __FILE__)
+
+require "bundler/setup"
+require "shakapacker"
+require "shakapacker/dev_server_runner"
+
+APP_ROOT = File.expand_path("..", __dir__)
+Dir.chdir(APP_ROOT) do
+  Shakapacker::DevServerRunner.run(ARGV)
+end
diff --git a/lib/install/config/webpacker.yml b/lib/install/config/shakapacker.yml
similarity index 86%
rename from lib/install/config/webpacker.yml
rename to lib/install/config/shakapacker.yml
index d40b92d06..df5184bf0 100644
--- a/lib/install/config/webpacker.yml
+++ b/lib/install/config/shakapacker.yml
@@ -1,15 +1,16 @@
-# Note: You must restart bin/webpacker-dev-server for changes to take effect
+# Note: You must restart bin/shakapacker-dev-server for changes to take effect
 
 default: &default
   source_path: app/javascript
 
   # You can have a subdirectory of the source_path, like 'packs' (recommended).
   # Alternatively, you can use '/' to use the whole source_path directory.
-  source_entry_path: /
+  # Notice that this is a relative path to source_path
+  source_entry_path: packs
 
   # If nested_entries is true, then we'll pick up subdirectories within the source_entry_path.
   # You cannot set this option to true if you set source_entry_path to '/'
-  nested_entries: false
+  nested_entries: true
 
   #  While using a File-System-based automated bundle generation feature, miscellaneous warnings suggesting css order
   #  conflicts may arise due to the mini-css-extract-plugin. For projects where css ordering has been mitigated through
@@ -19,10 +20,10 @@ default: &default
 
   public_root_path: public
   public_output_path: packs
-  cache_path: tmp/webpacker
+  cache_path: tmp/shakapacker
   webpack_compile_output: true
   # See https://github.com/shakacode/shakapacker#deployment
-  webpacker_precompile: true
+  shakapacker_precompile: true
 
   # Location for manifest.json, defaults to {public_output_path}/manifest.json if unset
   # manifest_path: public/packs/manifest.json
@@ -51,7 +52,11 @@ development:
   # Reference: https://webpack.js.org/configuration/dev-server/
   # Keys not described there are documented inline and in https://github.com/shakacode/shakapacker/
   dev_server:
-    https: false
+    # For running dev server with https, set `server: https`.
+    # You may use `https: true` instead but notice that it is deprecated in favor of `server: https`
+    # Ensure only one of these entries is set.
+    # server: https
+
     host: localhost
     port: 3035
     # Hot Module Replacement updates modules while the application is running without a full reload
@@ -78,8 +83,8 @@ development:
     # Should we use gzip compression?
     compress: true
     # Note that apps that do not check the host are vulnerable to DNS rebinding attacks
-    allowed_hosts: 'all'
-    # Shows progress and colorizes output of bin/webpacker[-dev-server]
+    allowed_hosts: 'auto'
+    # Shows progress and colorizes output of bin/shakapacker[-dev-server]
     pretty: true
     headers:
       'Access-Control-Allow-Origin': '*'
diff --git a/lib/install/template.rb b/lib/install/template.rb
index e1e10f7ac..1385d012b 100644
--- a/lib/install/template.rb
+++ b/lib/install/template.rb
@@ -1,11 +1,11 @@
-# Install Webpacker
-copy_file "#{__dir__}/config/webpacker.yml", "config/webpacker.yml"
+# Install Shakapacker
+copy_file "#{__dir__}/config/shakapacker.yml", "config/shakapacker.yml"
 copy_file "#{__dir__}/package.json", "package.json"
 
 say "Copying webpack core config"
 directory "#{__dir__}/config/webpack", "config/webpack"
 
-if Dir.exist?(Webpacker.config.source_path)
+if Dir.exist?(Shakapacker.config.source_path)
   say "The packs app source directory already exists"
 else
   say "Creating packs app source directory"
@@ -68,9 +68,9 @@
 results = []
 
 Dir.chdir(Rails.root) do
-  if Webpacker::VERSION.match?(/^[0-9]+\.[0-9]+\.[0-9]+$/)
-    say "Installing shakapacker@#{Webpacker::VERSION}"
-    results << run("yarn add shakapacker@#{Webpacker::VERSION} --exact")
+  if Shakapacker::VERSION.match?(/^[0-9]+\.[0-9]+\.[0-9]+$/)
+    say "Installing shakapacker@#{Shakapacker::VERSION}"
+    results << run("yarn add shakapacker@#{Shakapacker::VERSION} --exact")
   else
     say "Installing shakapacker@next"
     results << run("yarn add shakapacker@next --exact")
@@ -91,6 +91,6 @@
 end
 
 unless results.all?
-  say "Webpacker installation failed 😭 See above for details.", :red
+  say "Shakapacker installation failed 😭 See above for details.", :red
   exit 1
 end
diff --git a/lib/shakapacker.rb b/lib/shakapacker.rb
index 8ba0e8ed5..6148d6e10 100644
--- a/lib/shakapacker.rb
+++ b/lib/shakapacker.rb
@@ -1 +1,51 @@
-require "webpacker"
+require "active_support/core_ext/module/attribute_accessors"
+require "active_support/core_ext/string/inquiry"
+require "active_support/logger"
+require "active_support/tagged_logging"
+
+module Shakapacker
+  extend self
+
+  DEFAULT_ENV = "production".freeze
+
+  def instance=(instance)
+    @instance = instance
+  end
+
+  def instance
+    @instance ||= Shakapacker::Instance.new
+  end
+
+  def with_node_env(env)
+    original = ENV["NODE_ENV"]
+    ENV["NODE_ENV"] = env
+    yield
+  ensure
+    ENV["NODE_ENV"] = original
+  end
+
+  def ensure_log_goes_to_stdout
+    old_logger = Shakapacker.logger
+    Shakapacker.logger = Logger.new(STDOUT)
+    yield
+  ensure
+    Shakapacker.logger = old_logger
+  end
+
+  delegate :logger, :logger=, :env, :inlining_css?, to: :instance
+  delegate :config, :compiler, :manifest, :commands, :dev_server, to: :instance
+  delegate :bootstrap, :clean, :clobber, :compile, to: :commands
+end
+
+require "shakapacker/instance"
+require "shakapacker/env"
+require "shakapacker/configuration"
+require "shakapacker/manifest"
+require "shakapacker/compiler"
+require "shakapacker/commands"
+require "shakapacker/dev_server"
+require "shakapacker/deprecation_helper"
+
+require "shakapacker/railtie" if defined?(Rails)
+
+Webpacker = Shakapacker
diff --git a/lib/webpacker/base_strategy.rb b/lib/shakapacker/base_strategy.rb
similarity index 88%
rename from lib/webpacker/base_strategy.rb
rename to lib/shakapacker/base_strategy.rb
index 792792aeb..7cadc7626 100644
--- a/lib/webpacker/base_strategy.rb
+++ b/lib/shakapacker/base_strategy.rb
@@ -1,7 +1,7 @@
-module Webpacker
+module Shakapacker
   class BaseStrategy
     def initialize
-      @config = Webpacker.config
+      @config = Shakapacker.config
     end
 
     def after_compile_hook
diff --git a/lib/webpacker/commands.rb b/lib/shakapacker/commands.rb
similarity index 92%
rename from lib/webpacker/commands.rb
rename to lib/shakapacker/commands.rb
index 3116785b9..c3a60d67d 100644
--- a/lib/webpacker/commands.rb
+++ b/lib/shakapacker/commands.rb
@@ -1,8 +1,8 @@
-class Webpacker::Commands
-  delegate :config, :compiler, :manifest, :logger, to: :@webpacker
+class Shakapacker::Commands
+  delegate :config, :compiler, :manifest, :logger, to: :@instance
 
-  def initialize(webpacker)
-    @webpacker = webpacker
+  def initialize(instance)
+    @instance = instance
   end
 
   # Cleanup old assets in the compile directory. By default it will
diff --git a/lib/webpacker/compiler.rb b/lib/shakapacker/compiler.rb
similarity index 62%
rename from lib/webpacker/compiler.rb
rename to lib/shakapacker/compiler.rb
index 421153490..f5d3997f1 100644
--- a/lib/webpacker/compiler.rb
+++ b/lib/shakapacker/compiler.rb
@@ -1,17 +1,17 @@
 require "open3"
-require "webpacker/compiler_strategy"
+require "shakapacker/compiler_strategy"
 require "fileutils"
 
-class Webpacker::Compiler
+class Shakapacker::Compiler
   # Additional environment variables that the compiler is being run with
-  # Webpacker::Compiler.env['FRONTEND_API_KEY'] = 'your_secret_key'
+  # Shakapacker::Compiler.env['FRONTEND_API_KEY'] = 'your_secret_key'
   cattr_accessor(:env) { {} }
 
-  delegate :config, :logger, :strategy, to: :webpacker
+  delegate :config, :logger, :strategy, to: :instance
   delegate :fresh?, :stale?, :after_compile_hook, to: :strategy
 
-  def initialize(webpacker)
-    @webpacker = webpacker
+  def initialize(instance)
+    @instance = instance
   end
 
   def compile
@@ -33,7 +33,7 @@ def compile
   end
 
   private
-    attr_reader :webpacker
+    attr_reader :instance
 
     def acquire_ipc_lock
       open_lock_file do |lf|
@@ -73,8 +73,7 @@ def lock_file_path
     end
 
     def optionalRubyRunner
-      bin_webpack_path = config.root_path.join("bin/webpacker")
-      first_line = File.readlines(bin_webpack_path).first.chomp
+      first_line = File.readlines(bin_shakapacker_path).first.chomp
       /ruby/.match?(first_line) ? RbConfig.ruby : ""
     end
 
@@ -83,7 +82,7 @@ def run_webpack
 
       stdout, stderr, status = Open3.capture3(
         webpack_env,
-        "#{optionalRubyRunner} ./bin/webpacker",
+        "#{optionalRubyRunner} #{bin_shakapacker_path}",
         chdir: File.expand_path(config.root_path)
       )
 
@@ -105,8 +104,26 @@ def run_webpack
     def webpack_env
       return env unless defined?(ActionController::Base)
 
-      env.merge("WEBPACKER_ASSET_HOST"        => ENV.fetch("WEBPACKER_ASSET_HOST", ActionController::Base.helpers.compute_asset_host),
-                "WEBPACKER_RELATIVE_URL_ROOT" => ENV.fetch("WEBPACKER_RELATIVE_URL_ROOT", ActionController::Base.relative_url_root),
-                "WEBPACKER_CONFIG" => webpacker.config_path.to_s)
+      Shakapacker.set_shakapacker_env_variables_for_backward_compatibility
+
+      env.merge("SHAKAPACKER_ASSET_HOST"        => ENV.fetch("SHAKAPACKER_ASSET_HOST", ActionController::Base.helpers.compute_asset_host),
+                "SHAKAPACKER_RELATIVE_URL_ROOT" => ENV.fetch("SHAKAPACKER_RELATIVE_URL_ROOT", ActionController::Base.relative_url_root),
+                "SHAKAPACKER_CONFIG" => instance.config_path.to_s)
+    end
+
+    def bin_shakapacker_path
+      if File.exist?(config.root_path.join("bin/shakapacker"))
+        config.root_path.join("bin/shakapacker")
+      elsif File.exist?(config.root_path.join("bin/webpacker"))
+        Shakapacker.puts_deprecation_message(
+          Shakapacker.short_deprecation_message(
+            "bin/webpacker",
+            "bin/shakapacker"
+          )
+        )
+        config.root_path.join("bin/webpacker")
+      else
+        config.root_path.join("bin/shakapacker")
+      end
     end
 end
diff --git a/lib/webpacker/compiler_strategy.rb b/lib/shakapacker/compiler_strategy.rb
similarity index 54%
rename from lib/webpacker/compiler_strategy.rb
rename to lib/shakapacker/compiler_strategy.rb
index 92e3c21aa..93f6ddaa7 100644
--- a/lib/webpacker/compiler_strategy.rb
+++ b/lib/shakapacker/compiler_strategy.rb
@@ -1,16 +1,16 @@
-require "webpacker/mtime_strategy"
-require "webpacker/digest_strategy"
+require "shakapacker/mtime_strategy"
+require "shakapacker/digest_strategy"
 
-module Webpacker
+module Shakapacker
   class CompilerStrategy
     def self.from_config
-      strategy_from_config = Webpacker.config.compiler_strategy
+      strategy_from_config = Shakapacker.config.compiler_strategy
 
       case strategy_from_config
       when "mtime"
-        Webpacker::MtimeStrategy.new
+        Shakapacker::MtimeStrategy.new
       when "digest"
-        Webpacker::DigestStrategy.new
+        Shakapacker::DigestStrategy.new
       else
         raise "Unknown strategy '#{strategy_from_config}'. " \
               "Available options are 'mtime' and 'digest'."
diff --git a/lib/webpacker/configuration.rb b/lib/shakapacker/configuration.rb
similarity index 54%
rename from lib/webpacker/configuration.rb
rename to lib/shakapacker/configuration.rb
index 46620068d..86b6a9577 100644
--- a/lib/webpacker/configuration.rb
+++ b/lib/shakapacker/configuration.rb
@@ -2,7 +2,7 @@
 require "active_support/core_ext/hash/keys"
 require "active_support/core_ext/hash/indifferent_access"
 
-class Webpacker::Configuration
+class Shakapacker::Configuration
   class << self
     attr_accessor :installing
   end
@@ -11,8 +11,11 @@ class << self
 
   def initialize(root_path:, config_path:, env:)
     @root_path = root_path
-    @config_path = config_path
     @env = env
+
+    # For backward compatibility
+    Shakapacker.set_shakapacker_env_variables_for_backward_compatibility
+    @config_path = Pathname.new(ENV["SHAKAPACKER_CONFIG"] || config_path)
   end
 
   def dev_server
@@ -31,13 +34,24 @@ def ensure_consistent_versioning?
     fetch(:ensure_consistent_versioning)
   end
 
-  def webpacker_precompile?
+  def shakapacker_precompile?
     # ENV of false takes precedence
-    return false if %w(no false n f).include?(ENV["WEBPACKER_PRECOMPILE"])
-    return true if %w(yes true y t).include?(ENV["WEBPACKER_PRECOMPILE"])
+    return false if %w(no false n f).include?(ENV["SHAKAPACKER_PRECOMPILE"])
+    return true if %w(yes true y t).include?(ENV["SHAKAPACKER_PRECOMPILE"])
 
     return false unless config_path.exist?
-    fetch(:webpacker_precompile)
+    fetch(:shakapacker_precompile)
+  end
+
+  def webpacker_precompile?
+    Shakapacker.puts_deprecation_message(
+      Shakapacker.short_deprecation_message(
+        "webpacker_precompile?",
+        "shakapacker_precompile?"
+      )
+    )
+
+    shakapacker_precompile?
   end
 
   def source_path
@@ -49,7 +63,7 @@ def additional_paths
   end
 
   def source_entry_path
-    source_path.join(fetch(:source_entry_path))
+    source_path.join(relative_path(fetch(:source_entry_path)))
   end
 
   def manifest_path
@@ -82,7 +96,7 @@ def cache_path
 
   def check_yarn_integrity=(value)
     warn <<~EOS
-      Webpacker::Configuration#check_yarn_integrity=(value) is obsolete. The integrity
+      Shakapacker::Configuration#check_yarn_integrity=(value) is obsolete. The integrity
       check has been removed from Webpacker (https://github.com/rails/webpacker/pull/2518)
       so changing this setting will have no effect.
     EOS
@@ -97,7 +111,17 @@ def compiler_strategy
   end
 
   def fetch(key)
-    data.fetch(key, defaults[key])
+    return data.fetch(key, defaults[key]) unless key == :webpacker_precompile
+
+    # for backward compatibility
+    Shakapacker.puts_deprecation_message(
+      Shakapacker.short_deprecation_message(
+        "webpacker_precompile",
+        "shakapacker_precompile"
+      )
+    )
+
+    data.fetch(key, defaults[:shakapacker_precompile])
   end
 
   private
@@ -111,13 +135,22 @@ def load
       rescue ArgumentError
         YAML.load_file(config_path.to_s)
       end
-      config[env].deep_symbolize_keys
+      symbolized_config = config[env].deep_symbolize_keys
+
+      # For backward compatibility
+      if symbolized_config.key?(:shakapacker_precompile) && !symbolized_config.key?(:webpacker_precompile)
+        symbolized_config[:webpacker_precompile] = symbolized_config[:shakapacker_precompile]
+      elsif !symbolized_config.key?(:shakapacker_precompile) && symbolized_config.key?(:webpacker_precompile)
+        symbolized_config[:shakapacker_precompile] = symbolized_config[:webpacker_precompile]
+      end
+
+      return symbolized_config
     rescue Errno::ENOENT => e
       if self.class.installing
         {}
       else
-        raise "Webpacker configuration file not found #{config_path}. " \
-              "Please run rails webpacker:install " \
+        raise "Shakapacker configuration file not found #{config_path}. " \
+              "Please run rails shakapacker:install " \
               "Error: #{e.message}"
       end
     rescue Psych::SyntaxError => e
@@ -128,13 +161,19 @@ def load
 
     def defaults
       @defaults ||= begin
-        path = File.expand_path("../../install/config/webpacker.yml", __FILE__)
+        path = File.expand_path("../../install/config/shakapacker.yml", __FILE__)
         config = begin
           YAML.load_file(path, aliases: true)
         rescue ArgumentError
           YAML.load_file(path)
         end
-        HashWithIndifferentAccess.new(config[env] || config[Webpacker::DEFAULT_ENV])
+        HashWithIndifferentAccess.new(config[env] || config[Shakapacker::DEFAULT_ENV])
       end
     end
+
+    def relative_path(path)
+      return ".#{path}" if path.start_with?("/")
+
+      path
+    end
 end
diff --git a/lib/shakapacker/deprecation_helper.rb b/lib/shakapacker/deprecation_helper.rb
new file mode 100644
index 000000000..10950292b
--- /dev/null
+++ b/lib/shakapacker/deprecation_helper.rb
@@ -0,0 +1,88 @@
+module Shakapacker
+  DEPRECATION_GUIDE_URL = "https://github.com/shakacode/shakapacker/docs/v7_upgrade.md"
+  DEPRECATION_MESSAGE = <<~MSG
+    DEPRECATION NOTICE:
+
+    Using webpacker spelling is deprecated in Shakapacker.
+    Update your project with the new spelling.
+
+    For more information about this process, check:
+    #{DEPRECATION_GUIDE_URL}
+  MSG
+
+  def get_config_file_path_with_backward_compatibility(config_path)
+    if config_path.to_s.end_with?("shakapacker.yml") && !File.exist?(config_path)
+      webpacker_config_path = if config_path.class == Pathname
+        Pathname.new(config_path.to_s.gsub("shakapacker.yml", "webpacker.yml"))
+      else
+        config_path.gsub("shakapacker.yml", "webpacker.yml")
+      end
+
+      if File.exist?(webpacker_config_path)
+        puts_deprecation_message(
+          short_deprecation_message(
+            "config/webpacker.yml",
+            "config/shakapacker.yml"
+          )
+        )
+        return webpacker_config_path
+      end
+    end
+
+    config_path
+  end
+
+  def set_shakapacker_env_variables_for_backward_compatibility
+    webpacker_env_variables = ENV.select { |key| key.start_with?("WEBPACKER_") }
+
+    deprecation_message_body = ""
+
+    webpacker_env_variables.each do |webpacker_key, _|
+      shakapacker_key = webpacker_key.gsub("WEBPACKER_", "SHAKAPACKER_")
+      next if ENV.key?(shakapacker_key)
+
+      deprecation_message_body += <<~MSG
+        Use `#{shakapacker_key}` instead of the deprecated `#{webpacker_key}`.
+      MSG
+
+      ENV[shakapacker_key] = ENV[webpacker_key]
+    end
+
+    if deprecation_message_body.present?
+      Shakapacker.puts_deprecation_message(
+        <<~MSG
+          DEPRECATION NOTICE:
+
+          #{deprecation_message_body}
+          Read more: #{Shakapacker::DEPRECATION_GUIDE_URL}
+        MSG
+      )
+    end
+  end
+
+  def short_deprecation_message(old_usage, new_usage)
+    <<~MSG
+      DEPRECATION NOTICE:
+
+      Consider using `#{new_usage}` instead of the deprecated `#{old_usage}`.
+      Read more: #{DEPRECATION_GUIDE_URL}
+    MSG
+  end
+
+  def puts_deprecation_message(message)
+    puts <<~MSG
+      \e[33m
+      #{message}
+      \e[0m
+    MSG
+  end
+
+  def puts_rake_deprecation_message(webpacker_task_name)
+    Shakapacker.puts_deprecation_message(
+      Shakapacker.short_deprecation_message(
+        "rake #{webpacker_task_name}",
+        "rake #{webpacker_task_name.gsub("webpacker", "shakapacker")}"
+      )
+    )
+  end
+end
diff --git a/lib/webpacker/dev_server.rb b/lib/shakapacker/dev_server.rb
similarity index 63%
rename from lib/webpacker/dev_server.rb
rename to lib/shakapacker/dev_server.rb
index f7c27e908..79ef43d73 100644
--- a/lib/webpacker/dev_server.rb
+++ b/lib/shakapacker/dev_server.rb
@@ -1,8 +1,8 @@
-class Webpacker::DevServer
-  DEFAULT_ENV_PREFIX = "WEBPACKER_DEV_SERVER".freeze
+class Shakapacker::DevServer
+  DEFAULT_ENV_PREFIX = "SHAKAPACKER_DEV_SERVER".freeze
 
   # Configure dev server connection timeout (in seconds), default: 0.1
-  # Webpacker.dev_server.connect_timeout = 1
+  # Shakapacker.dev_server.connect_timeout = 1
   cattr_accessor(:connect_timeout) { 0.1 }
 
   attr_reader :config
@@ -39,8 +39,29 @@ def https?
     end
   end
 
+  def server
+    server_value = fetch(:server)
+    server_type = server_value.is_a?(Hash) ? server_value[:type] : server_value
+
+    return server_type if ["http", "https"].include?(server_type)
+
+    return "http" if server_type.nil?
+
+    puts <<~MSG
+    WARNING:
+    `server: #{server_type}` is not a valid configuration in Shakapacker.
+    Falling back to default `server: http`.
+    MSG
+
+    "http"
+  rescue KeyError
+    "http"
+  end
+
   def protocol
-    https? ? "https" : "http"
+    return "https" if server == "https" || https? == true
+
+    "http"
   end
 
   def host_with_port
@@ -73,6 +94,8 @@ def fetch(key)
       return nil unless config.dev_server.present?
 
       ENV["#{env_prefix}_#{key.upcase}"] || config.dev_server.fetch(key, defaults[key])
+    rescue
+      nil
     end
 
     def defaults
diff --git a/lib/webpacker/dev_server_proxy.rb b/lib/shakapacker/dev_server_proxy.rb
similarity index 80%
rename from lib/webpacker/dev_server_proxy.rb
rename to lib/shakapacker/dev_server_proxy.rb
index 577a08ff2..81bce5f68 100644
--- a/lib/webpacker/dev_server_proxy.rb
+++ b/lib/shakapacker/dev_server_proxy.rb
@@ -1,10 +1,10 @@
 require "rack/proxy"
 
-class Webpacker::DevServerProxy < Rack::Proxy
-  delegate :config, :dev_server, to: :@webpacker
+class Shakapacker::DevServerProxy < Rack::Proxy
+  delegate :config, :dev_server, to: :@instance
 
   def initialize(app = nil, opts = {})
-    @webpacker = opts.delete(:webpacker) || Webpacker.instance
+    @instance = opts.delete(:shakapacker) || Shakapacker.instance
     opts[:streaming] = false if Rails.env.test? && !opts.key?(:streaming)
     super
   end
@@ -15,7 +15,7 @@ def perform_request(env)
       env["HTTP_X_FORWARDED_SERVER"] = dev_server.host_with_port
       env["HTTP_PORT"] = env["HTTP_X_FORWARDED_PORT"] = dev_server.port.to_s
       env["HTTP_X_FORWARDED_PROTO"] = env["HTTP_X_FORWARDED_SCHEME"] = dev_server.protocol
-      unless dev_server.https?
+      unless dev_server.protocol == "https"
         env["HTTPS"] = env["HTTP_X_FORWARDED_SSL"] = "off"
       end
       env["SCRIPT_NAME"] = ""
diff --git a/lib/shakapacker/dev_server_runner.rb b/lib/shakapacker/dev_server_runner.rb
new file mode 100644
index 000000000..6d3e45945
--- /dev/null
+++ b/lib/shakapacker/dev_server_runner.rb
@@ -0,0 +1,104 @@
+require "shellwords"
+require "socket"
+require "shakapacker/configuration"
+require "shakapacker/dev_server"
+require "shakapacker/runner"
+
+module Shakapacker
+  class DevServerRunner < Shakapacker::Runner
+    def run
+      load_config
+      detect_unsupported_switches!
+      detect_port!
+      execute_cmd
+    end
+
+    private
+
+      def load_config
+        app_root = Pathname.new(@app_path)
+
+        @config = Configuration.new(
+          root_path: app_root,
+          config_path: Pathname.new(@shakapacker_config),
+          env: ENV["RAILS_ENV"]
+        )
+
+        dev_server = DevServer.new(@config)
+
+        @hostname          = dev_server.host
+        @port              = dev_server.port
+        @pretty            = dev_server.pretty?
+        @https             = dev_server.protocol == "https"
+        @hot               = dev_server.hmr?
+
+      rescue Errno::ENOENT, NoMethodError
+        $stdout.puts "webpack dev_server configuration not found in #{@config.config_path}[#{ENV["RAILS_ENV"]}]."
+        $stdout.puts "Please run bundle exec rails shakapacker:install to install Shakapacker"
+        exit!
+      end
+
+      UNSUPPORTED_SWITCHES = %w[--host --port]
+      private_constant :UNSUPPORTED_SWITCHES
+      def detect_unsupported_switches!
+        unsupported_switches = UNSUPPORTED_SWITCHES & @argv
+        if unsupported_switches.any?
+          $stdout.puts "The following CLI switches are not supported by Shakapacker: #{unsupported_switches.join(' ')}. Please edit your command and try again."
+          exit!
+        end
+
+        if @argv.include?("--https") && !@https
+          $stdout.puts "Please set https: true in shakapacker.yml to use the --https command line flag."
+          exit!
+        end
+      end
+
+      def detect_port!
+        server = TCPServer.new(@hostname, @port)
+        server.close
+
+      rescue Errno::EADDRINUSE
+        $stdout.puts "Another program is running on port #{@port}. Set a new port in #{@config.config_path} for dev_server"
+        exit!
+      end
+
+      def execute_cmd
+        env = Shakapacker::Compiler.env
+        env["SHAKAPACKER_CONFIG"] = @shakapacker_config
+        env["WEBPACK_SERVE"] = "true"
+
+        cmd = if node_modules_bin_exist?
+          ["#{@node_modules_bin_path}/webpack", "serve"]
+        else
+          ["yarn", "webpack", "serve"]
+        end
+
+        if @argv.include?("--debug-webpacker")
+          Shakapacker.puts_deprecation_message(
+            Shakapacker.short_deprecation_message(
+              "--debug-webpacker",
+              "--debug-shakapacker"
+            )
+          )
+        end
+
+        if @argv.delete("--debug-shakapacker") || @argv.delete("--debug-webpacker")
+          cmd = [ "node", "--inspect-brk", "--trace-warnings" ] + cmd
+        end
+
+        cmd += ["--config", @webpack_config]
+        cmd += ["--progress", "--color"] if @pretty
+
+        cmd += ["--hot"] if @hot
+        cmd += @argv
+
+        Dir.chdir(@app_path) do
+          Kernel.exec env, *cmd
+        end
+      end
+
+      def node_modules_bin_exist?
+        File.exist?("#{@node_modules_bin_path}/webpack-dev-server")
+      end
+  end
+end
diff --git a/lib/webpacker/digest_strategy.rb b/lib/shakapacker/digest_strategy.rb
similarity index 84%
rename from lib/webpacker/digest_strategy.rb
rename to lib/shakapacker/digest_strategy.rb
index 9dbbe43a3..65eadff15 100644
--- a/lib/webpacker/digest_strategy.rb
+++ b/lib/shakapacker/digest_strategy.rb
@@ -1,7 +1,7 @@
 require "digest/sha1"
-require "webpacker/base_strategy"
+require "shakapacker/base_strategy"
 
-module Webpacker
+module Shakapacker
   class DigestStrategy < BaseStrategy
     # Returns true if all the compiled packs are up to date with the underlying asset files.
     def fresh?
@@ -31,10 +31,10 @@ def last_compilation_digest
       def watched_files_digest
         if Rails.env.development?
           warn <<~MSG.strip
-          Webpacker::Compiler - Slow setup for development
+          Shakapacker::Compiler - Slow setup for development
           Prepare JS assets with either:
-          1. Running `bin/webpacker-dev-server`
-          2. Set `compile` to false in webpacker.yml and run `bin/webpacker -w`
+          1. Running `bin/shakapacker-dev-server`
+          2. Set `compile` to false in shakapacker.yml and run `bin/shakapacker -w`
         MSG
         end
 
@@ -53,7 +53,7 @@ def record_compilation_digest
       end
 
       def compilation_digest_path
-        config.cache_path.join("last-compilation-digest-#{Webpacker.env}")
+        config.cache_path.join("last-compilation-digest-#{Shakapacker.env}")
       end
   end
 end
diff --git a/lib/webpacker/env.rb b/lib/shakapacker/env.rb
similarity index 71%
rename from lib/webpacker/env.rb
rename to lib/shakapacker/env.rb
index cd71efe36..5e8f4d3e4 100644
--- a/lib/webpacker/env.rb
+++ b/lib/shakapacker/env.rb
@@ -1,17 +1,17 @@
-class Webpacker::Env
-  delegate :config_path, :logger, to: :@webpacker
+class Shakapacker::Env
+  delegate :config_path, :logger, to: :@instance
 
-  def self.inquire(webpacker)
-    new(webpacker).inquire
+  def self.inquire(instance)
+    new(instance).inquire
   end
 
-  def initialize(webpacker)
-    @webpacker = webpacker
+  def initialize(instance)
+    @instance = instance
   end
 
   def inquire
     fallback_env_warning if config_path.exist? && !current
-    current || Webpacker::DEFAULT_ENV.inquiry
+    current || Shakapacker::DEFAULT_ENV.inquiry
   end
 
   private
@@ -20,7 +20,7 @@ def current
     end
 
     def fallback_env_warning
-      logger.info "RAILS_ENV=#{Rails.env} environment is not defined in config/webpacker.yml, falling back to #{Webpacker::DEFAULT_ENV} environment"
+      logger.info "RAILS_ENV=#{Rails.env} environment is not defined in config/shakapacker.yml, falling back to #{Shakapacker::DEFAULT_ENV} environment"
     end
 
     def available_environments
diff --git a/lib/webpacker/helper.rb b/lib/shakapacker/helper.rb
similarity index 87%
rename from lib/webpacker/helper.rb
rename to lib/shakapacker/helper.rb
index ee0630407..0b739cffc 100644
--- a/lib/webpacker/helper.rb
+++ b/lib/shakapacker/helper.rb
@@ -1,12 +1,12 @@
-module Webpacker::Helper
-  # Returns the current Webpacker instance.
-  # Could be overridden to use multiple Webpacker
+module Shakapacker::Helper
+  # Returns the current Shakapacker instance.
+  # Could be overridden to use multiple Shakapacker
   # configurations within the same app (e.g. with engines).
-  def current_webpacker_instance
-    Webpacker.instance
+  def current_shakapacker_instance
+    Shakapacker.instance
   end
 
-  # Computes the relative path for a given Webpacker asset.
+  # Computes the relative path for a given Shakapacker asset.
   # Returns the relative path using manifest.json and passes it to path_to_asset helper.
   # This will use path_to_asset internally, so most of their behaviors will be the same.
   #
@@ -14,10 +14,10 @@ def current_webpacker_instance
   #
   #   <%= asset_pack_path 'calendar.css' %> # => "/packs/calendar-1016838bab065ae1e122.css"
   def asset_pack_path(name, **options)
-    path_to_asset(current_webpacker_instance.manifest.lookup!(name), options)
+    path_to_asset(current_shakapacker_instance.manifest.lookup!(name), options)
   end
 
-  # Computes the absolute path for a given Webpacker asset.
+  # Computes the absolute path for a given Shakapacker asset.
   # Returns the absolute path using manifest.json and passes it to url_to_asset helper.
   # This will use url_to_asset internally, so most of their behaviors will be the same.
   #
@@ -25,17 +25,17 @@ def asset_pack_path(name, **options)
   #
   #   <%= asset_pack_url 'calendar.css' %> # => "http://example.com/packs/calendar-1016838bab065ae1e122.css"
   def asset_pack_url(name, **options)
-    url_to_asset(current_webpacker_instance.manifest.lookup!(name), options)
+    url_to_asset(current_shakapacker_instance.manifest.lookup!(name), options)
   end
 
-  # Computes the relative path for a given Webpacker image with the same automated processing as image_pack_tag.
+  # Computes the relative path for a given Shakapacker image with the same automated processing as image_pack_tag.
   # Returns the relative path using manifest.json and passes it to path_to_asset helper.
   # This will use path_to_asset internally, so most of their behaviors will be the same.
   def image_pack_path(name, **options)
     resolve_path_to_image(name, **options)
   end
 
-  # Computes the absolute path for a given Webpacker image with the same automated
+  # Computes the absolute path for a given Shakapacker image with the same automated
   # processing as image_pack_tag. Returns the relative path using manifest.json
   # and passes it to path_to_asset helper. This will use path_to_asset internally,
   # so most of their behaviors will be the same.
@@ -114,7 +114,7 @@ def javascript_pack_tag(*names, defer: true, **options)
     end
   end
 
-  # Creates a link tag, for preloading, that references a given Webpacker asset.
+  # Creates a link tag, for preloading, that references a given Shakapacker asset.
   # In production mode, the digested reference is automatically looked up.
   # See: https://developer.mozilla.org/en-US/docs/Web/HTML/Preloading_content
   #
@@ -124,7 +124,7 @@ def javascript_pack_tag(*names, defer: true, **options)
   #   <link rel="preload" href="/packs/fonts/fa-regular-400-944fb546bd7018b07190a32244f67dc9.woff2" as="font" type="font/woff2" crossorigin="anonymous">
   def preload_pack_asset(name, **options)
     if self.class.method_defined?(:preload_link_tag)
-      preload_link_tag(current_webpacker_instance.manifest.lookup!(name), options)
+      preload_link_tag(current_shakapacker_instance.manifest.lookup!(name), options)
     else
       raise "You need Rails >= 5.2 to use this tag."
     end
@@ -156,7 +156,7 @@ def preload_pack_asset(name, **options)
   #   <%= stylesheet_pack_tag 'calendar' %>
   #   <%= stylesheet_pack_tag 'map' %>
   def stylesheet_pack_tag(*names, **options)
-    return "" if Webpacker.inlining_css?
+    return "" if Shakapacker.inlining_css?
 
     requested_packs = sources_from_manifest_entrypoints(names, type: :stylesheet)
     appended_packs = available_sources_from_manifest_entrypoints(@stylesheet_pack_tag_queue || [], type: :stylesheet)
@@ -213,17 +213,17 @@ def javascript_pack_tag_queue
     end
 
     def sources_from_manifest_entrypoints(names, type:)
-      names.map { |name| current_webpacker_instance.manifest.lookup_pack_with_chunks!(name.to_s, type: type) }.flatten.uniq
+      names.map { |name| current_shakapacker_instance.manifest.lookup_pack_with_chunks!(name.to_s, type: type) }.flatten.uniq
     end
 
     def available_sources_from_manifest_entrypoints(names, type:)
-      names.map { |name| current_webpacker_instance.manifest.lookup_pack_with_chunks(name.to_s, type: type) }.flatten.compact.uniq
+      names.map { |name| current_shakapacker_instance.manifest.lookup_pack_with_chunks(name.to_s, type: type) }.flatten.compact.uniq
     end
 
     def resolve_path_to_image(name, **options)
       path = name.starts_with?("static/") ? name : "static/#{name}"
-      path_to_asset(current_webpacker_instance.manifest.lookup!(path), options)
+      path_to_asset(current_shakapacker_instance.manifest.lookup!(path), options)
     rescue
-      path_to_asset(current_webpacker_instance.manifest.lookup!(name), options)
+      path_to_asset(current_shakapacker_instance.manifest.lookup!(name), options)
     end
 end
diff --git a/lib/webpacker/instance.rb b/lib/shakapacker/instance.rb
similarity index 52%
rename from lib/webpacker/instance.rb
rename to lib/shakapacker/instance.rb
index 0e9cba411..38bfc8682 100644
--- a/lib/webpacker/instance.rb
+++ b/lib/shakapacker/instance.rb
@@ -1,20 +1,23 @@
 require "pathname"
-class Webpacker::Instance
+
+class Shakapacker::Instance
   cattr_accessor(:logger) { ActiveSupport::TaggedLogging.new(ActiveSupport::Logger.new(STDOUT)) }
 
   attr_reader :root_path, :config_path
 
-  def initialize(root_path: Rails.root, config_path: Rails.root.join("config/webpacker.yml"))
+  def initialize(root_path: Rails.root, config_path: Rails.root.join("config/shakapacker.yml"))
     @root_path = root_path
-    @config_path = Pathname.new(ENV["WEBPACKER_CONFIG"] || config_path)
+
+    # For backward compatibility
+    @config_path = Shakapacker.get_config_file_path_with_backward_compatibility(config_path)
   end
 
   def env
-    @env ||= Webpacker::Env.inquire self
+    @env ||= Shakapacker::Env.inquire self
   end
 
   def config
-    @config ||= Webpacker::Configuration.new(
+    @config ||= Shakapacker::Configuration.new(
       root_path: root_path,
       config_path: config_path,
       env: env
@@ -22,23 +25,23 @@ def config
   end
 
   def strategy
-    @strategy ||= Webpacker::CompilerStrategy.from_config
+    @strategy ||= Shakapacker::CompilerStrategy.from_config
   end
 
   def compiler
-    @compiler ||= Webpacker::Compiler.new self
+    @compiler ||= Shakapacker::Compiler.new self
   end
 
   def dev_server
-    @dev_server ||= Webpacker::DevServer.new config
+    @dev_server ||= Shakapacker::DevServer.new config
   end
 
   def manifest
-    @manifest ||= Webpacker::Manifest.new self
+    @manifest ||= Shakapacker::Manifest.new self
   end
 
   def commands
-    @commands ||= Webpacker::Commands.new self
+    @commands ||= Shakapacker::Commands.new self
   end
 
   def inlining_css?
diff --git a/lib/webpacker/manifest.rb b/lib/shakapacker/manifest.rb
similarity index 74%
rename from lib/webpacker/manifest.rb
rename to lib/shakapacker/manifest.rb
index dc9073f52..3b2bd1bb7 100644
--- a/lib/webpacker/manifest.rb
+++ b/lib/shakapacker/manifest.rb
@@ -4,14 +4,14 @@
 # "/packs/calendar-1016838bab065ae1e314.css".
 #
 # When the configuration is set to on-demand compilation, with the `compile: true` option in
-# the webpacker.yml file, any lookups will be preceded by a compilation if one is needed.
-class Webpacker::Manifest
+# the shakapacker.yml file, any lookups will be preceded by a compilation if one is needed.
+class Shakapacker::Manifest
   class MissingEntryError < StandardError; end
 
-  delegate :config, :compiler, :dev_server, to: :@webpacker
+  delegate :config, :compiler, :dev_server, to: :@instance
 
-  def initialize(webpacker)
-    @webpacker = webpacker
+  def initialize(instance)
+    @instance = instance
   end
 
   def refresh
@@ -32,19 +32,19 @@ def lookup_pack_with_chunks!(name, pack_type = {})
     lookup_pack_with_chunks(name, pack_type) || handle_missing_entry(name, pack_type)
   end
 
-  # Computes the relative path for a given Webpacker asset using manifest.json.
+  # Computes the relative path for a given Shakapacker asset using manifest.json.
   # If no asset is found, returns nil.
   #
   # Example:
   #
-  #   Webpacker.manifest.lookup('calendar.js') # => "/packs/calendar-1016838bab065ae1e122.js"
+  #   Shakapacker.manifest.lookup('calendar.js') # => "/packs/calendar-1016838bab065ae1e122.js"
   def lookup(name, pack_type = {})
     compile if compiling?
 
     find(full_pack_name(name, pack_type[:type]))
   end
 
-  # Like lookup, except that if no asset is found, raises a Webpacker::Manifest::MissingEntryError.
+  # Like lookup, except that if no asset is found, raises a Shakapacker::Manifest::MissingEntryError.
   def lookup!(name, pack_type = {})
     lookup(name, pack_type) || handle_missing_entry(name, pack_type)
   end
@@ -55,7 +55,7 @@ def compiling?
     end
 
     def compile
-      Webpacker.logger.tagged("Webpacker") { compiler.compile }
+      Shakapacker.logger.tagged("Shakapacker") { compiler.compile }
     end
 
     def data
@@ -76,7 +76,7 @@ def full_pack_name(name, pack_type)
     end
 
     def handle_missing_entry(name, pack_type)
-      raise Webpacker::Manifest::MissingEntryError, missing_file_from_manifest_error(full_pack_name(name, pack_type[:type]))
+      raise Shakapacker::Manifest::MissingEntryError, missing_file_from_manifest_error(full_pack_name(name, pack_type[:type]))
     end
 
     def load
@@ -106,11 +106,11 @@ def missing_file_from_manifest_error(bundle_name)
       <<-MSG
 Shakapacker can't find #{bundle_name} in #{config.manifest_path}. Possible causes:
 1. You forgot to install node packages (try `yarn install`) or are running an incompatible version of Node
-2. Your app has code with a non-standard extension (like a `.jsx` file) but the extension is not in the `extensions` config in `config/webpacker.yml`
-3. You have set compile: false (see `config/webpacker.yml`) for this environment
-   (unless you are using the `bin/webpacker -w` or the `bin/webpacker-dev-server`, in which case maybe you aren't running the dev server in the background?)
+2. Your app has code with a non-standard extension (like a `.jsx` file) but the extension is not in the `extensions` config in `config/shakapacker.yml`
+3. You have set compile: false (see `config/shakapacker.yml`) for this environment
+   (unless you are using the `bin/shakapacker -w` or the `bin/shakapacker-dev-server`, in which case maybe you aren't running the dev server in the background?)
 4. webpack has not yet FINISHED running to reflect updates.
-5. You have misconfigured Webpacker's `config/webpacker.yml` file.
+5. You have misconfigured Shakapacker's `config/shakapacker.yml` file.
 6. Your webpack configuration is not creating a manifest.
 
 Your manifest contains:
diff --git a/lib/webpacker/mtime_strategy.rb b/lib/shakapacker/mtime_strategy.rb
similarity index 79%
rename from lib/webpacker/mtime_strategy.rb
rename to lib/shakapacker/mtime_strategy.rb
index 87c98fcd7..a33dac490 100644
--- a/lib/webpacker/mtime_strategy.rb
+++ b/lib/shakapacker/mtime_strategy.rb
@@ -1,6 +1,6 @@
-require "webpacker/base_strategy"
+require "shakapacker/base_strategy"
 
-module Webpacker
+module Shakapacker
   class MtimeStrategy < BaseStrategy
     # Returns true if manifest file mtime is newer than the timestamp of the last modified watched file
     def fresh?
@@ -21,11 +21,11 @@ def manifest_mtime
       def latest_modified_timestamp
         if Rails.env.development?
           warn <<~MSG.strip
-          Webpacker::Compiler - Slow setup for development
+          Shakapacker::Compiler - Slow setup for development
 
           Prepare JS assets with either:
-          1. Running `bin/webpacker-dev-server`
-          2. Set `compile` to false in webpacker.yml and run `bin/webpacker -w`
+          1. Running `bin/shakapacker-dev-server`
+          2. Set `compile` to false in shakapacker.yml and run `bin/shakapacker -w`
         MSG
         end
 
diff --git a/lib/shakapacker/railtie.rb b/lib/shakapacker/railtie.rb
new file mode 100644
index 000000000..d73fe259a
--- /dev/null
+++ b/lib/shakapacker/railtie.rb
@@ -0,0 +1,70 @@
+require "rails/railtie"
+
+require "shakapacker/helper"
+require "shakapacker/dev_server_proxy"
+require "shakapacker/version_checker"
+
+class Shakapacker::Engine < ::Rails::Engine
+  # Allows Shakapacker config values to be set via Rails env config files
+  config.shakapacker = ActiveSupport::OrderedOptions.new
+
+  initializer "shakapacker.version_checker" do
+    if File.exist?(Shakapacker::VersionChecker::NodePackageVersion.package_json_path)
+      Shakapacker::VersionChecker.build.raise_if_gem_and_node_package_versions_differ
+    end
+  end
+
+  initializer "shakapacker.proxy" do |app|
+    if (Shakapacker.config.dev_server.present? rescue nil)
+      app.middleware.insert_before 0,
+        Rails::VERSION::MAJOR >= 5 ?
+          Shakapacker::DevServerProxy : "Shakapacker::DevServerProxy", ssl_verify_none: true
+    end
+  end
+
+  initializer "shakapacker.helper" do
+    ActiveSupport.on_load :action_controller do
+      ActionController::Base.helper Shakapacker::Helper
+    end
+
+    ActiveSupport.on_load :action_view do
+      include Shakapacker::Helper
+    end
+  end
+
+  initializer "shakapacker.logger" do
+    config.after_initialize do
+      if ::Rails.logger.respond_to?(:tagged)
+        Shakapacker.logger = ::Rails.logger
+      else
+        Shakapacker.logger = ActiveSupport::TaggedLogging.new(::Rails.logger)
+      end
+    end
+  end
+
+  initializer "shakapacker.bootstrap" do
+    if defined?(Rails::Server) || defined?(Rails::Console)
+      Shakapacker.bootstrap
+      if defined?(Spring)
+        require "spring/watcher"
+        Spring.after_fork { Shakapacker.bootstrap }
+        Spring.watch(Shakapacker.config.config_path)
+      end
+    end
+  end
+
+  initializer "shakapacker.set_source" do |app|
+    if Shakapacker.config.config_path.exist?
+      app.config.javascript_path = Shakapacker.config.source_path.relative_path_from(Rails.root.join("app")).to_s
+    end
+  end
+
+  initializer "shakapacker.remove_app_packs_from_the_autoload_paths" do
+    Rails.application.config.before_initialize do
+      if Shakapacker.config.config_path.exist?
+        source_path = Shakapacker.config.source_path.to_s
+        ActiveSupport::Dependencies.autoload_paths.delete(source_path)
+      end
+    end
+  end
+end
diff --git a/lib/shakapacker/runner.rb b/lib/shakapacker/runner.rb
new file mode 100644
index 000000000..5c8074375
--- /dev/null
+++ b/lib/shakapacker/runner.rb
@@ -0,0 +1,28 @@
+module Shakapacker
+  class Runner
+    def self.run(argv)
+      $stdout.sync = true
+      ENV["NODE_ENV"] ||= (ENV["RAILS_ENV"] == "production") ? "production" : "development"
+      new(argv).run
+    end
+
+    def initialize(argv)
+      @argv = argv
+
+      @app_path              = File.expand_path(".", Dir.pwd)
+      @webpack_config        = File.join(@app_path, "config/webpack/webpack.config.js")
+
+      Shakapacker.set_shakapacker_env_variables_for_backward_compatibility
+
+      @node_modules_bin_path = ENV["SHAKAPACKER_NODE_MODULES_BIN_PATH"] || `yarn bin`.chomp
+      @shakapacker_config    = ENV["SHAKAPACKER_CONFIG"] || File.join(@app_path, "config/shakapacker.yml")
+
+      @shakapacker_config = Shakapacker.get_config_file_path_with_backward_compatibility(@shakapacker_config)
+
+      unless File.exist?(@webpack_config)
+        $stderr.puts "webpack config #{@webpack_config} not found, please run 'bundle exec rails shakapacker:install' to install Shakapacker with default configs or add the missing config file for your custom environment."
+        exit!
+      end
+    end
+  end
+end
diff --git a/lib/shakapacker/utils/version_syntax_converter.rb b/lib/shakapacker/utils/version_syntax_converter.rb
index 7c5733ca0..122798a63 100644
--- a/lib/shakapacker/utils/version_syntax_converter.rb
+++ b/lib/shakapacker/utils/version_syntax_converter.rb
@@ -1,11 +1,11 @@
 # frozen_string_literal: true
 
-require_relative "../../webpacker/version"
+require_relative "../../shakapacker/version"
 
 module Shakapacker
   module Utils
     class VersionSyntaxConverter
-      def rubygem_to_npm(rubygem_version = Webpacker::VERSION)
+      def rubygem_to_npm(rubygem_version = Shakapacker::VERSION)
         regex_match = rubygem_version.match(/(\d+\.\d+\.\d+)[.\-]?(.+)?/)
         return "#{regex_match[1]}-#{regex_match[2]}" if regex_match[2]
 
diff --git a/lib/webpacker/version.rb b/lib/shakapacker/version.rb
similarity index 81%
rename from lib/webpacker/version.rb
rename to lib/shakapacker/version.rb
index 3fcef26a6..e5d0e7037 100644
--- a/lib/webpacker/version.rb
+++ b/lib/shakapacker/version.rb
@@ -1,4 +1,4 @@
-module Webpacker
+module Shakapacker
   # Change the version in package.json too, please!
   VERSION = "6.6.0".freeze
 end
diff --git a/lib/webpacker/version_checker.rb b/lib/shakapacker/version_checker.rb
similarity index 92%
rename from lib/webpacker/version_checker.rb
rename to lib/shakapacker/version_checker.rb
index 8c5721880..15cd3f0c6 100644
--- a/lib/webpacker/version_checker.rb
+++ b/lib/shakapacker/version_checker.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
-require "webpacker/version"
+require "shakapacker/version"
 
-module Webpacker
+module Shakapacker
   class VersionChecker
     attr_reader :node_package_version
 
@@ -27,7 +27,7 @@ def raise_if_gem_and_node_package_versions_differ
 
       uses_wildcard = node_package_version.semver_wildcard?
 
-      if !Webpacker.config.ensure_consistent_versioning? && (uses_wildcard || !versions_match)
+      if !Shakapacker.config.ensure_consistent_versioning? && (uses_wildcard || !versions_match)
         check_failed = if uses_wildcard
           "Semver wildcard without a lockfile detected"
         else
@@ -35,13 +35,13 @@ def raise_if_gem_and_node_package_versions_differ
         end
 
         warn <<-MSG.strip_heredoc
-          Webpacker::VersionChecker - #{check_failed}
+          Shakapacker::VersionChecker - #{check_failed}
 
           You are currently not checking for consistent versions of shakapacker gem and npm package. A version mismatch or usage of semantic versioning wildcard (~ or ^) without a lockfile has been detected.
 
           Version mismatch can lead to incorrect behavior and bugs. You should ensure that both the gem and npm package dependencies are locked to the same version.
 
-          You can enable the version check by setting `ensure_consistent_versioning: true` in your `webpacker.yml` file.
+          You can enable the version check by setting `ensure_consistent_versioning: true` in your `shakapacker.yml` file.
 
           Checking for gem and npm package versions mismatch or wildcard will be enabled by default in the next major version of shakapacker.
         MSG
@@ -68,18 +68,18 @@ def common_error_msg
       end
 
       def raise_differing_versions_warning
-        msg = "**ERROR** Webpacker: Webpacker gem and node package versions do not match\n#{common_error_msg}"
+        msg = "**ERROR** Shakapacker: Shakapacker gem and node package versions do not match\n#{common_error_msg}"
         raise msg
       end
 
       def raise_node_semver_version_warning
-        msg = "**ERROR** Webpacker: Your node package version for shakapacker contains a "\
+        msg = "**ERROR** Shakapacker: Your node package version for shakapacker contains a "\
               "^ or ~\n#{common_error_msg}"
         raise msg
       end
 
       def gem_version
-        Webpacker::VERSION
+        Shakapacker::VERSION
       end
 
       def gem_major_minor_patch_version
diff --git a/lib/shakapacker/webpack_runner.rb b/lib/shakapacker/webpack_runner.rb
new file mode 100644
index 000000000..6589c9c65
--- /dev/null
+++ b/lib/shakapacker/webpack_runner.rb
@@ -0,0 +1,67 @@
+require "shellwords"
+require "shakapacker/runner"
+
+module Shakapacker
+  class WebpackRunner < Shakapacker::Runner
+    WEBPACK_COMMANDS = [
+      "help",
+      "h",
+      "--help",
+      "-h",
+      "version",
+      "v",
+      "--version",
+      "-v",
+      "info",
+      "i"
+    ].freeze
+
+    def run
+      env = Shakapacker::Compiler.env
+      env["SHAKAPACKER_CONFIG"] = @shakapacker_config
+
+      cmd = if node_modules_bin_exist?
+        ["#{@node_modules_bin_path}/webpack"]
+      else
+        ["yarn", "webpack"]
+      end
+
+      if @argv.include?("--debug-webpacker")
+        Shakapacker.puts_deprecation_message(
+          Shakapacker.short_deprecation_message(
+            "--debug-webpacker",
+            "--debug-shakapacker"
+          )
+        )
+      end
+
+      if @argv.delete("--debug-shakapacker") || @argv.delete("--debug-webpacker")
+        cmd = ["node", "--inspect-brk"] + cmd
+      end
+
+      if @argv.delete "--trace-deprecation"
+        cmd = ["node", "--trace-deprecation"] + cmd
+      end
+
+      if @argv.delete "--no-deprecation"
+        cmd = ["node", "--no-deprecation"] + cmd
+      end
+
+      # Webpack commands are not compatible with --config option.
+      if (@argv & WEBPACK_COMMANDS).empty?
+        cmd += ["--config", @webpack_config]
+      end
+
+      cmd += @argv
+
+      Dir.chdir(@app_path) do
+        Kernel.exec env, *cmd
+      end
+    end
+
+    private
+      def node_modules_bin_exist?
+        File.exist?("#{@node_modules_bin_path}/webpack")
+      end
+  end
+end
diff --git a/lib/tasks/shakapacker.rake b/lib/tasks/shakapacker.rake
new file mode 100644
index 000000000..032e9e419
--- /dev/null
+++ b/lib/tasks/shakapacker.rake
@@ -0,0 +1,18 @@
+tasks = {
+  "shakapacker:info"                    => "Provides information on Shakapacker's environment",
+  "shakapacker:install"                 => "Installs and setup webpack with Yarn",
+  "shakapacker:compile"                 => "Compiles webpack bundles based on environment",
+  "shakapacker:clean"                   => "Remove old compiled bundles",
+  "shakapacker:clobber"                 => "Removes the webpack compiled output directory",
+  "shakapacker:check_node"              => "Verifies if Node.js is installed",
+  "shakapacker:check_yarn"              => "Verifies if Yarn is installed",
+  "shakapacker:check_binstubs"          => "Verifies that bin/shakapacker is present",
+  "shakapacker:binstubs"                => "Installs Shakapacker binstubs in this application",
+  "shakapacker:verify_install"          => "Verifies if Shakapacker is installed",
+}.freeze
+
+desc "Lists all available tasks in Shakapacker"
+task :shakapacker do
+  puts "Available Shakapacker tasks are:"
+  tasks.each { |task, message| puts task.ljust(30) + message }
+end
diff --git a/lib/tasks/shakapacker/binstubs.rake b/lib/tasks/shakapacker/binstubs.rake
new file mode 100644
index 000000000..44a08a069
--- /dev/null
+++ b/lib/tasks/shakapacker/binstubs.rake
@@ -0,0 +1,15 @@
+binstubs_template_path = File.expand_path("../../install/binstubs.rb", __dir__).freeze
+bin_path = ENV["BUNDLE_BIN"] || Rails.root.join("bin")
+
+namespace :shakapacker do
+  desc "Installs Shakapacker binstubs in this application"
+  task binstubs: [:check_node, :check_yarn] do |task|
+    prefix = task.name.split(/#|shakapacker:binstubs/).first
+
+    if Rails::VERSION::MAJOR >= 5
+      exec "#{RbConfig.ruby} #{bin_path}/rails #{prefix}app:template LOCATION='#{binstubs_template_path}'"
+    else
+      exec "#{RbConfig.ruby} #{bin_path}/rake #{prefix}rails:template LOCATION='#{binstubs_template_path}'"
+    end
+  end
+end
diff --git a/lib/tasks/shakapacker/check_binstubs.rake b/lib/tasks/shakapacker/check_binstubs.rake
new file mode 100644
index 000000000..1fc7446e0
--- /dev/null
+++ b/lib/tasks/shakapacker/check_binstubs.rake
@@ -0,0 +1,25 @@
+namespace :shakapacker do
+  desc "Verifies that bin/shakapacker is present"
+  task :check_binstubs do
+    if File.exist?(Rails.root.join("bin/shakapacker"))
+      exit
+    elsif File.exist?(Rails.root.join("bin/webpacker"))
+      Shakapacker.puts_deprecation_message(
+        Shakapacker.short_deprecation_message(
+          "bin/webpacker",
+          "bin/shakapacker"
+        )
+      )
+      exit
+    else
+      puts <<~MSG
+        Could't find shakapacker binstubs!
+        Possible solutions:
+         - Ensure you have run `rails shakapacker:install`.
+         - Run `rails shakapacker:binstubs` if you have already installed shakapacker.
+         - Ensure the `bin` directory and `bin/shakapacker` are not included in .gitignore.
+      MSG
+      exit!
+    end
+  end
+end
diff --git a/lib/tasks/shakapacker/check_node.rake b/lib/tasks/shakapacker/check_node.rake
new file mode 100644
index 000000000..d33d7f5fc
--- /dev/null
+++ b/lib/tasks/shakapacker/check_node.rake
@@ -0,0 +1,31 @@
+require "semantic_range"
+namespace :shakapacker do
+  desc "Verifies if Node.js is installed"
+  task :check_node do
+    begin
+      node_version = `node -v || nodejs -v`.strip
+      raise Errno::ENOENT if node_version.blank?
+
+      pkg_path = Pathname.new("#{__dir__}/../../../package.json").realpath
+      node_range = JSON.parse(pkg_path.read)["engines"]["node"]
+      is_valid = SemanticRange.satisfies?(node_version, node_range) rescue false
+      semver_major = node_version[/\d+/] rescue nil
+      is_unstable = semver_major.to_i.odd? rescue false
+
+      if is_unstable
+        $stderr.puts "Warning: you are using an unstable release of Node.js (#{node_version}). If you encounter issues with Node.js, consider switching to an Active LTS release. More info: https://docs.npmjs.com/try-the-latest-stable-version-of-node"
+      end
+
+      unless is_valid
+        $stderr.puts "Shakapacker requires Node.js \"#{node_range}\" and you are using #{node_version}"
+        $stderr.puts "Please upgrade Node.js https://nodejs.org/en/download/"
+        $stderr.puts "Exiting!"
+        exit!
+      end
+    rescue Errno::ENOENT
+      $stderr.puts "Node.js not installed. Please download and install Node.js https://nodejs.org/en/download/"
+      $stderr.puts "Exiting!"
+      exit!
+    end
+  end
+end
diff --git a/lib/tasks/shakapacker/check_yarn.rake b/lib/tasks/shakapacker/check_yarn.rake
new file mode 100644
index 000000000..d0ef257ad
--- /dev/null
+++ b/lib/tasks/shakapacker/check_yarn.rake
@@ -0,0 +1,33 @@
+require "semantic_range"
+namespace :shakapacker do
+  desc "Verifies if Yarn is installed"
+  task :check_yarn do
+    begin
+      which_command = Gem.win_platform? ? "where" : "which"
+      raise Errno::ENOENT if `#{which_command} yarn`.strip.empty?
+
+      yarn_version = `yarn --version`.strip
+      raise Errno::ENOENT if yarn_version.blank?
+
+      pkg_path = Pathname.new("#{__dir__}/../../../package.json").realpath
+      yarn_range = JSON.parse(pkg_path.read)["engines"]["yarn"]
+      is_valid = SemanticRange.satisfies?(yarn_version, yarn_range) rescue false
+      is_unsupported = SemanticRange.satisfies?(yarn_version, ">=4.0.0") rescue false
+
+      unless is_valid
+        $stderr.puts "Shakapacker requires Yarn \"#{yarn_range}\" and you are using #{yarn_version}"
+        if is_unsupported
+          $stderr.puts "This version of Shakapacker does not support Yarn #{yarn_version}. Please downgrade to a supported version of Yarn https://yarnpkg.com/lang/en/docs/install/"
+        else
+          $stderr.puts "Please upgrade Yarn https://yarnpkg.com/lang/en/docs/install/"
+        end
+        $stderr.puts "Exiting!"
+        exit!
+      end
+    rescue Errno::ENOENT
+      $stderr.puts "Yarn not installed. Please download and install Yarn from https://yarnpkg.com/lang/en/docs/install/"
+      $stderr.puts "Exiting!"
+      exit!
+    end
+  end
+end
diff --git a/lib/tasks/shakapacker/clean.rake b/lib/tasks/shakapacker/clean.rake
new file mode 100644
index 000000000..bf97877b9
--- /dev/null
+++ b/lib/tasks/shakapacker/clean.rake
@@ -0,0 +1,23 @@
+$stdout.sync = true
+
+require "shakapacker/configuration"
+
+namespace :shakapacker do
+  desc "Remove old compiled bundles"
+  task :clean, [:keep, :age] => ["shakapacker:verify_install", :environment] do |_, args|
+    Shakapacker.ensure_log_goes_to_stdout do
+      Shakapacker.clean(Integer(args.keep || 2), Integer(args.age || 3600))
+    end
+  end
+end
+
+if Shakapacker.config.shakapacker_precompile?
+  # Run clean if the assets:clean is run
+  if Rake::Task.task_defined?("assets:clean")
+    Rake::Task["assets:clean"].enhance do
+      Rake::Task["shakapacker:clean"].invoke
+    end
+  else
+    Rake::Task.define_task("assets:clean" => "shakapacker:clean")
+  end
+end
diff --git a/lib/tasks/shakapacker/clobber.rake b/lib/tasks/shakapacker/clobber.rake
new file mode 100644
index 000000000..ef6bc9fae
--- /dev/null
+++ b/lib/tasks/shakapacker/clobber.rake
@@ -0,0 +1,18 @@
+require "shakapacker/configuration"
+
+namespace :shakapacker do
+  desc "Remove the webpack compiled output directory"
+  task clobber: ["shakapacker:verify_config", :environment] do
+    Shakapacker.clobber
+    $stdout.puts "Removed webpack output path directory #{Shakapacker.config.public_output_path}"
+  end
+end
+
+if Shakapacker.config.shakapacker_precompile?
+  # Run clobber if the assets:clobber is run
+  if Rake::Task.task_defined?("assets:clobber")
+    Rake::Task["assets:clobber"].enhance do
+      Rake::Task["shakapacker:clobber"].invoke
+    end
+  end
+end
diff --git a/lib/tasks/shakapacker/compile.rake b/lib/tasks/shakapacker/compile.rake
new file mode 100644
index 000000000..f246858dd
--- /dev/null
+++ b/lib/tasks/shakapacker/compile.rake
@@ -0,0 +1,31 @@
+$stdout.sync = true
+
+namespace :shakapacker do
+  desc "Compile JavaScript packs using webpack for production with digests"
+  task compile: ["shakapacker:verify_install", :environment] do
+    Shakapacker.with_node_env(ENV.fetch("NODE_ENV", "production")) do
+      Shakapacker.ensure_log_goes_to_stdout do
+        if Shakapacker.compile
+          # Successful compilation!
+        else
+          # Failed compilation
+          exit!
+        end
+      end
+    end
+  end
+end
+
+def invoke_shakapacker_compile_in_assets_precompile_task
+  Rake::Task["assets:precompile"].enhance do |task|
+    prefix = task.name.split(/#|assets:precompile/).first
+
+    Rake::Task["#{prefix}shakapacker:compile"].invoke
+  end
+end
+
+if Shakapacker.config.shakapacker_precompile?
+  if Rake::Task.task_defined?("assets:precompile")
+    invoke_shakapacker_compile_in_assets_precompile_task
+  end
+end
diff --git a/lib/tasks/shakapacker/info.rake b/lib/tasks/shakapacker/info.rake
new file mode 100644
index 000000000..e5be3c867
--- /dev/null
+++ b/lib/tasks/shakapacker/info.rake
@@ -0,0 +1,21 @@
+require "shakapacker/version"
+
+namespace :shakapacker do
+  desc "Provide information on Shakapacker's environment"
+  task :info do
+    Dir.chdir(Rails.root) do
+      $stdout.puts "Ruby: #{`ruby --version`}"
+      $stdout.puts "Rails: #{Rails.version}"
+      $stdout.puts "Shakapacker: #{Shakapacker::VERSION}"
+      $stdout.puts "Node: #{`node --version`}"
+      $stdout.puts "Yarn: #{`yarn --version`}"
+
+      $stdout.puts "\n"
+      $stdout.puts "shakapacker: \n#{`npm list shakapacker version`}"
+
+      $stdout.puts "Is bin/shakapacker present?: #{File.exist? 'bin/shakapacker'}"
+      $stdout.puts "Is bin/shakapacker-dev-server present?: #{File.exist? 'bin/shakapacker-dev-server'}"
+      $stdout.puts "Is bin/yarn present?: #{File.exist? 'bin/yarn'}"
+    end
+  end
+end
diff --git a/lib/tasks/shakapacker/install.rake b/lib/tasks/shakapacker/install.rake
new file mode 100644
index 000000000..78f2ca74e
--- /dev/null
+++ b/lib/tasks/shakapacker/install.rake
@@ -0,0 +1,17 @@
+install_template_path = File.expand_path("../../install/template.rb", __dir__).freeze
+bin_path = ENV["BUNDLE_BIN"] || Rails.root.join("bin")
+
+namespace :shakapacker do
+  desc "Install Shakapacker in this application"
+  task install: [:check_node, :check_yarn] do |task|
+    Shakapacker::Configuration.installing = true
+
+    prefix = task.name.split(/#|shakapacker:install/).first
+
+    if Rails::VERSION::MAJOR >= 5
+      exec "#{RbConfig.ruby} #{bin_path}/rails #{prefix}app:template LOCATION='#{install_template_path}'"
+    else
+      exec "#{RbConfig.ruby} #{bin_path}/rake #{prefix}rails:template LOCATION='#{install_template_path}'"
+    end
+  end
+end
diff --git a/lib/tasks/shakapacker/verify_config.rake b/lib/tasks/shakapacker/verify_config.rake
new file mode 100644
index 000000000..687365dd9
--- /dev/null
+++ b/lib/tasks/shakapacker/verify_config.rake
@@ -0,0 +1,12 @@
+namespace :shakapacker do
+  desc "Verifies if the Shakapacker config is present"
+  task :verify_config do
+    unless Shakapacker.config.config_path.exist?
+      path = Shakapacker.config.config_path.relative_path_from(Pathname.new(pwd)).to_s
+      $stderr.puts "Configuration #{path} file not found. \n"\
+           "Make sure shakapacker:install is run successfully before " \
+           "running dependent tasks"
+      exit!
+    end
+  end
+end
diff --git a/lib/tasks/shakapacker/verify_install.rake b/lib/tasks/shakapacker/verify_install.rake
new file mode 100644
index 000000000..843aaa16e
--- /dev/null
+++ b/lib/tasks/shakapacker/verify_install.rake
@@ -0,0 +1,4 @@
+namespace :shakapacker do
+  desc "Verifies if Shakapacker is installed"
+  task verify_install: [:verify_config, :check_node, :check_yarn, :check_binstubs]
+end
diff --git a/lib/tasks/shakapacker/yarn_install.rake b/lib/tasks/shakapacker/yarn_install.rake
new file mode 100644
index 000000000..266bb4132
--- /dev/null
+++ b/lib/tasks/shakapacker/yarn_install.rake
@@ -0,0 +1,24 @@
+namespace :shakapacker do
+  desc "Support for older Rails versions. Install all JavaScript dependencies as specified via Yarn"
+  task :yarn_install do
+    warn <<~MSG.strip
+      Shakapacker - Automatic installation of yarn packages is deprecated
+      Automatic installation of yarn packages when assets are precompiled is deprecated and will be removed in Shakapacker v7.
+      Please ensure you are installing yarn packages explicitly before the asset compilation.
+    MSG
+
+    valid_node_envs = %w[test development production]
+    node_env = ENV.fetch("NODE_ENV") do
+      valid_node_envs.include?(Rails.env) ? Rails.env : "production"
+    end
+    Dir.chdir(Rails.root) do
+      yarn_flags =
+        if `yarn --version`.start_with?("1")
+          "--no-progress --frozen-lockfile"
+        else
+          "--immutable"
+        end
+      system({ "NODE_ENV" => node_env }, "yarn install #{yarn_flags}")
+    end
+  end
+end
diff --git a/lib/tasks/webpacker.rake b/lib/tasks/webpacker.rake
index c619f62d2..797a0d247 100644
--- a/lib/tasks/webpacker.rake
+++ b/lib/tasks/webpacker.rake
@@ -1,18 +1,20 @@
 tasks = {
-  "webpacker:info"                    => "Provides information on Webpacker's environment",
-  "webpacker:install"                 => "Installs and setup webpack with Yarn",
-  "webpacker:compile"                 => "Compiles webpack bundles based on environment",
-  "webpacker:clean"                   => "Remove old compiled webpacks",
-  "webpacker:clobber"                 => "Removes the webpack compiled output directory",
-  "webpacker:check_node"              => "Verifies if Node.js is installed",
-  "webpacker:check_yarn"              => "Verifies if Yarn is installed",
-  "webpacker:check_binstubs"          => "Verifies that bin/webpacker is present",
-  "webpacker:binstubs"                => "Installs Webpacker binstubs in this application",
-  "webpacker:verify_install"          => "Verifies if Webpacker is installed",
+  "webpacker:info"                    => "DEPRECATED - Provides information on Shakapacker's environment",
+  "webpacker:install"                 => "DEPRECATED - Installs and setup webpack with Yarn",
+  "webpacker:compile"                 => "DEPRECATED - Compiles webpack bundles based on environment",
+  "webpacker:clean"                   => "DEPRECATED - Remove old compiled bundles",
+  "webpacker:clobber"                 => "DEPRECATED - Removes the webpack compiled output directory",
+  "webpacker:check_node"              => "DEPRECATED - Verifies if Node.js is installed",
+  "webpacker:check_yarn"              => "DEPRECATED - Verifies if Yarn is installed",
+  "webpacker:check_binstubs"          => "DEPRECATED - Verifies that bin/shakapacker is present",
+  "webpacker:binstubs"                => "DEPRECATED - Installs Shakapacker binstubs in this application",
+  "webpacker:verify_install"          => "DEPRECATED - Verifies if Shakapacker is installed",
 }.freeze
 
-desc "Lists all available tasks in Webpacker"
-task :webpacker do
-  puts "Available Webpacker tasks are:"
+desc "DEPRECATED - Lists all available tasks in Webpacker"
+task :webpacker do |task|
+  puts "DEPRECATED - Available Webpacker tasks are:"
   tasks.each { |task, message| puts task.ljust(30) + message }
+
+  Shakapacker.puts_rake_deprecation_message(task.name)
 end
diff --git a/lib/tasks/webpacker/binstubs.rake b/lib/tasks/webpacker/binstubs.rake
index a7853ed28..7cce2e839 100644
--- a/lib/tasks/webpacker/binstubs.rake
+++ b/lib/tasks/webpacker/binstubs.rake
@@ -1,15 +1,9 @@
-binstubs_template_path = File.expand_path("../../install/binstubs.rb", __dir__).freeze
-bin_path = ENV["BUNDLE_BIN"] || Rails.root.join("bin")
-
 namespace :webpacker do
-  desc "Installs Webpacker binstubs in this application"
-  task binstubs: [:check_node, :check_yarn] do |task|
-    prefix = task.name.split(/#|webpacker:binstubs/).first
+  desc "DEPRECATED - Installs Shakapacker binstubs in this application"
+  task :binstubs do |task|
+    Shakapacker.puts_rake_deprecation_message(task.name)
 
-    if Rails::VERSION::MAJOR >= 5
-      exec "#{RbConfig.ruby} #{bin_path}/rails #{prefix}app:template LOCATION='#{binstubs_template_path}'"
-    else
-      exec "#{RbConfig.ruby} #{bin_path}/rake #{prefix}rails:template LOCATION='#{binstubs_template_path}'"
-    end
+    prefix = task.name.split(/#|webpacker:/).first
+    Rake::Task["#{prefix}shakapacker:binstubs"].invoke
   end
 end
diff --git a/lib/tasks/webpacker/check_binstubs.rake b/lib/tasks/webpacker/check_binstubs.rake
index 335f3f7cb..652833208 100644
--- a/lib/tasks/webpacker/check_binstubs.rake
+++ b/lib/tasks/webpacker/check_binstubs.rake
@@ -1,12 +1,9 @@
 namespace :webpacker do
-  desc "Verifies that bin/webpacker is present"
-  task :check_binstubs do
-    unless File.exist?(Rails.root.join("bin/webpacker"))
-      $stderr.puts "webpacker binstub not found.\n"\
-           "Have you run rails webpacker:install ?\n"\
-           "Make sure the bin directory and bin/webpacker are not included in .gitignore\n"\
-           "Exiting!"
-      exit!
-    end
+  desc "DEPRECATED - Verifies that bin/shakapacker is present"
+  task :check_binstubs do |task|
+    Shakapacker.puts_rake_deprecation_message(task.name)
+
+    prefix = task.name.split(/#|webpacker:/).first
+    Rake::Task["#{prefix}shakapacker:check_binstubs"].invoke
   end
 end
diff --git a/lib/tasks/webpacker/check_node.rake b/lib/tasks/webpacker/check_node.rake
index 3ee5fdf4f..bada31ebb 100644
--- a/lib/tasks/webpacker/check_node.rake
+++ b/lib/tasks/webpacker/check_node.rake
@@ -1,31 +1,9 @@
-require "semantic_range"
 namespace :webpacker do
-  desc "Verifies if Node.js is installed"
-  task :check_node do
-    begin
-      node_version = `node -v || nodejs -v`.strip
-      raise Errno::ENOENT if node_version.blank?
+  desc "DEPRECATED - Verifies if Node.js is installed"
+  task :check_node do |task|
+    Shakapacker.puts_rake_deprecation_message(task.name)
 
-      pkg_path = Pathname.new("#{__dir__}/../../../package.json").realpath
-      node_range = JSON.parse(pkg_path.read)["engines"]["node"]
-      is_valid = SemanticRange.satisfies?(node_version, node_range) rescue false
-      semver_major = node_version[/\d+/] rescue nil
-      is_unstable = semver_major.to_i.odd? rescue false
-
-      if is_unstable
-        $stderr.puts "Warning: you are using an unstable release of Node.js (#{node_version}). If you encounter issues with Node.js, consider switching to an Active LTS release. More info: https://docs.npmjs.com/try-the-latest-stable-version-of-node"
-      end
-
-      unless is_valid
-        $stderr.puts "Webpacker requires Node.js \"#{node_range}\" and you are using #{node_version}"
-        $stderr.puts "Please upgrade Node.js https://nodejs.org/en/download/"
-        $stderr.puts "Exiting!"
-        exit!
-      end
-    rescue Errno::ENOENT
-      $stderr.puts "Node.js not installed. Please download and install Node.js https://nodejs.org/en/download/"
-      $stderr.puts "Exiting!"
-      exit!
-    end
+    prefix = task.name.split(/#|webpacker:/).first
+    Rake::Task["#{prefix}shakapacker:check_node"].invoke
   end
 end
diff --git a/lib/tasks/webpacker/check_yarn.rake b/lib/tasks/webpacker/check_yarn.rake
index 292c4ded6..d2dac6311 100644
--- a/lib/tasks/webpacker/check_yarn.rake
+++ b/lib/tasks/webpacker/check_yarn.rake
@@ -1,33 +1,9 @@
-require "semantic_range"
 namespace :webpacker do
-  desc "Verifies if Yarn is installed"
-  task :check_yarn do
-    begin
-      which_command = Gem.win_platform? ? "where" : "which"
-      raise Errno::ENOENT if `#{which_command} yarn`.strip.empty?
+  desc "DEPRECATED - Verifies if Yarn is installed"
+  task :check_yarn do |task|
+    Shakapacker.puts_rake_deprecation_message(task.name)
 
-      yarn_version = `yarn --version`.strip
-      raise Errno::ENOENT if yarn_version.blank?
-
-      pkg_path = Pathname.new("#{__dir__}/../../../package.json").realpath
-      yarn_range = JSON.parse(pkg_path.read)["engines"]["yarn"]
-      is_valid = SemanticRange.satisfies?(yarn_version, yarn_range) rescue false
-      is_unsupported = SemanticRange.satisfies?(yarn_version, ">=4.0.0") rescue false
-
-      unless is_valid
-        $stderr.puts "Webpacker requires Yarn \"#{yarn_range}\" and you are using #{yarn_version}"
-        if is_unsupported
-          $stderr.puts "This version of Webpacker does not support Yarn #{yarn_version}. Please downgrade to a supported version of Yarn https://yarnpkg.com/lang/en/docs/install/"
-        else
-          $stderr.puts "Please upgrade Yarn https://yarnpkg.com/lang/en/docs/install/"
-        end
-        $stderr.puts "Exiting!"
-        exit!
-      end
-    rescue Errno::ENOENT
-      $stderr.puts "Yarn not installed. Please download and install Yarn from https://yarnpkg.com/lang/en/docs/install/"
-      $stderr.puts "Exiting!"
-      exit!
-    end
+    prefix = task.name.split(/#|webpacker:/).first
+    Rake::Task["#{prefix}shakapacker:check_yarn"].invoke
   end
 end
diff --git a/lib/tasks/webpacker/clean.rake b/lib/tasks/webpacker/clean.rake
index 260e53e8f..15121ea8c 100644
--- a/lib/tasks/webpacker/clean.rake
+++ b/lib/tasks/webpacker/clean.rake
@@ -1,23 +1,9 @@
-$stdout.sync = true
-
-require "webpacker/configuration"
-
 namespace :webpacker do
-  desc "Remove old compiled webpacks"
-  task :clean, [:keep, :age] => ["webpacker:verify_install", :environment] do |_, args|
-    Webpacker.ensure_log_goes_to_stdout do
-      Webpacker.clean(Integer(args.keep || 2), Integer(args.age || 3600))
-    end
-  end
-end
+  desc "DEPRECATED - Remove old compiled bundles"
+  task :clean, [:keep, :age] do |task, args|
+    Shakapacker.puts_rake_deprecation_message(task.name)
 
-if Webpacker.config.webpacker_precompile?
-  # Run clean if the assets:clean is run
-  if Rake::Task.task_defined?("assets:clean")
-    Rake::Task["assets:clean"].enhance do
-      Rake::Task["webpacker:clean"].invoke
-    end
-  else
-    Rake::Task.define_task("assets:clean" => "webpacker:clean")
+    prefix = task.name.split(/#|webpacker:/).first
+    Rake::Task["#{prefix}shakapacker:clean"].invoke(args.keep, args.age)
   end
 end
diff --git a/lib/tasks/webpacker/clobber.rake b/lib/tasks/webpacker/clobber.rake
index ae7c0312b..66f42606e 100644
--- a/lib/tasks/webpacker/clobber.rake
+++ b/lib/tasks/webpacker/clobber.rake
@@ -1,18 +1,11 @@
-require "webpacker/configuration"
+require "shakapacker/configuration"
 
 namespace :webpacker do
-  desc "Remove the webpack compiled output directory"
-  task clobber: ["webpacker:verify_config", :environment] do
-    Webpacker.clobber
-    $stdout.puts "Removed webpack output path directory #{Webpacker.config.public_output_path}"
-  end
-end
+  desc "DEPRECATED - Remove the webpack compiled output directory"
+  task :clobber do |task|
+    Shakapacker.puts_rake_deprecation_message(task.name)
 
-if Webpacker.config.webpacker_precompile?
-  # Run clobber if the assets:clobber is run
-  if Rake::Task.task_defined?("assets:clobber")
-    Rake::Task["assets:clobber"].enhance do
-      Rake::Task["webpacker:clobber"].invoke
-    end
+    prefix = task.name.split(/#|webpacker:/).first
+    Rake::Task["#{prefix}shakapacker:clobber"].invoke
   end
 end
diff --git a/lib/tasks/webpacker/compile.rake b/lib/tasks/webpacker/compile.rake
index ec537961d..90038da85 100644
--- a/lib/tasks/webpacker/compile.rake
+++ b/lib/tasks/webpacker/compile.rake
@@ -1,37 +1,9 @@
-$stdout.sync = true
-
-def enhance_assets_precompile
-  Rake::Task["assets:precompile"].enhance do |task|
-    prefix = task.name.split(/#|assets:precompile/).first
-
-    Rake::Task["#{prefix}webpacker:compile"].invoke
-  end
-end
-
 namespace :webpacker do
-  desc "Compile JavaScript packs using webpack for production with digests"
-  task compile: ["webpacker:verify_install", :environment] do
-    Webpacker.with_node_env(ENV.fetch("NODE_ENV", "production")) do
-      Webpacker.ensure_log_goes_to_stdout do
-        if Webpacker.compile
-          # Successful compilation!
-        else
-          # Failed compilation
-          exit!
-        end
-      end
-    end
-  end
-end
+  desc "DEPRECATED - Compile JavaScript packs using webpack for production with digests"
+  task :compile do |task|
+    Shakapacker.puts_rake_deprecation_message(task.name)
 
-if Webpacker.config.webpacker_precompile?
-  if Rake::Task.task_defined?("assets:precompile")
-    # Rails already adds `yarn install` after 5.2
-    # https://github.com/shakacode/shakapacker/issues/237
-    enhance_assets_precompile
-  else
-    # Only add `yarn install` if Rails was not doing it (precompile was not defined).
-    # TODO: Remove this in Shakapacker 7.0
-    Rake::Task.define_task("assets:precompile" => ["webpacker:yarn_install", "webpacker:compile"])
+    prefix = task.name.split(/#|webpacker:/).first
+    Rake::Task["#{prefix}shakapacker:compile"].invoke
   end
 end
diff --git a/lib/tasks/webpacker/info.rake b/lib/tasks/webpacker/info.rake
index 705d1f02c..44a27140d 100644
--- a/lib/tasks/webpacker/info.rake
+++ b/lib/tasks/webpacker/info.rake
@@ -1,21 +1,9 @@
-require "webpacker/version"
-
 namespace :webpacker do
-  desc "Provide information on Webpacker's environment"
-  task :info do
-    Dir.chdir(Rails.root) do
-      $stdout.puts "Ruby: #{`ruby --version`}"
-      $stdout.puts "Rails: #{Rails.version}"
-      $stdout.puts "Webpacker: #{Webpacker::VERSION}"
-      $stdout.puts "Node: #{`node --version`}"
-      $stdout.puts "Yarn: #{`yarn --version`}"
-
-      $stdout.puts "\n"
-      $stdout.puts "shakapacker: \n#{`npm list shakapacker version`}"
+  desc "DEPRECATED - Provide information on Shakapacker's environment"
+  task :info do |task|
+    Shakapacker.puts_rake_deprecation_message(task.name)
 
-      $stdout.puts "Is bin/webpacker present?: #{File.exist? 'bin/webpacker'}"
-      $stdout.puts "Is bin/webpacker-dev-server present?: #{File.exist? 'bin/webpacker-dev-server'}"
-      $stdout.puts "Is bin/yarn present?: #{File.exist? 'bin/yarn'}"
-    end
+    prefix = task.name.split(/#|webpacker:/).first
+    Rake::Task["#{prefix}shakapacker:info"].invoke
   end
 end
diff --git a/lib/tasks/webpacker/install.rake b/lib/tasks/webpacker/install.rake
index 2fb130b3c..3885797ba 100644
--- a/lib/tasks/webpacker/install.rake
+++ b/lib/tasks/webpacker/install.rake
@@ -1,17 +1,9 @@
-install_template_path = File.expand_path("../../install/template.rb", __dir__).freeze
-bin_path = ENV["BUNDLE_BIN"] || Rails.root.join("bin")
-
 namespace :webpacker do
-  desc "Install Webpacker in this application"
-  task install: [:check_node, :check_yarn] do |task|
-    Webpacker::Configuration.installing = true
-
-    prefix = task.name.split(/#|webpacker:install/).first
+  desc "DEPRECATED - Install Shakapacker in this application"
+  task :install do |task|
+    Shakapacker.puts_rake_deprecation_message(task.name)
 
-    if Rails::VERSION::MAJOR >= 5
-      exec "#{RbConfig.ruby} #{bin_path}/rails #{prefix}app:template LOCATION='#{install_template_path}'"
-    else
-      exec "#{RbConfig.ruby} #{bin_path}/rake #{prefix}rails:template LOCATION='#{install_template_path}'"
-    end
+    prefix = task.name.split(/#|webpacker:/).first
+    Rake::Task["#{prefix}shakapacker:install"].invoke
   end
 end
diff --git a/lib/tasks/webpacker/verify_config.rake b/lib/tasks/webpacker/verify_config.rake
index daed6d365..cc23805b1 100644
--- a/lib/tasks/webpacker/verify_config.rake
+++ b/lib/tasks/webpacker/verify_config.rake
@@ -1,14 +1,9 @@
-require "webpacker/configuration"
-
 namespace :webpacker do
-  desc "Verifies if the Webpacker config is present"
-  task :verify_config do
-    unless Webpacker.config.config_path.exist?
-      path = Webpacker.config.config_path.relative_path_from(Pathname.new(pwd)).to_s
-      $stderr.puts "Configuration #{path} file not found. \n"\
-           "Make sure webpacker:install is run successfully before " \
-           "running dependent tasks"
-      exit!
-    end
+  desc "DEPRECATED - Verifies if the Shakapacker config is present"
+  task :verify_config do |task|
+    Shakapacker.puts_rake_deprecation_message(task.name)
+
+    prefix = task.name.split(/#|webpacker:/).first
+    Rake::Task["#{prefix}shakapacker:verify_config"].invoke
   end
 end
diff --git a/lib/tasks/webpacker/verify_install.rake b/lib/tasks/webpacker/verify_install.rake
index ce02d0ac3..eb5e6528f 100644
--- a/lib/tasks/webpacker/verify_install.rake
+++ b/lib/tasks/webpacker/verify_install.rake
@@ -1,4 +1,9 @@
 namespace :webpacker do
-  desc "Verifies if Webpacker is installed"
-  task verify_install: [:verify_config, :check_node, :check_yarn, :check_binstubs]
+  desc "DEPRECATED - Verifies if Shakapacker is installed"
+  task :verify_install do |task|
+    Shakapacker.puts_rake_deprecation_message(task.name)
+
+    prefix = task.name.split(/#|webpacker:/).first
+    Rake::Task["#{prefix}shakapacker:verify_install"].invoke
+  end
 end
diff --git a/lib/tasks/webpacker/yarn_install.rake b/lib/tasks/webpacker/yarn_install.rake
index fb2c7fd1f..71d7802e1 100644
--- a/lib/tasks/webpacker/yarn_install.rake
+++ b/lib/tasks/webpacker/yarn_install.rake
@@ -1,24 +1,9 @@
 namespace :webpacker do
-  desc "Support for older Rails versions. Install all JavaScript dependencies as specified via Yarn"
-  task :yarn_install do
-    warn <<~MSG.strip
-      Shakapacker - Automatic installation of yarn packages is deprecated
-      Automatic installation of yarn packages when assets are precompiled is deprecated and will be removed in Shakapacker v7.
-      Please ensure you are installing yarn packages explicitly before the asset compilation.
-    MSG
+  desc "DEPRECATED - Support for older Rails versions. Install all JavaScript dependencies as specified via Yarn"
+  task :yarn_install do |task|
+    Shakapacker.puts_rake_deprecation_message(task.name)
 
-    valid_node_envs = %w[test development production]
-    node_env = ENV.fetch("NODE_ENV") do
-      valid_node_envs.include?(Rails.env) ? Rails.env : "production"
-    end
-    Dir.chdir(Rails.root) do
-      yarn_flags =
-        if `yarn --version`.start_with?("1")
-          "--no-progress --frozen-lockfile"
-        else
-          "--immutable"
-        end
-      system({ "NODE_ENV" => node_env }, "yarn install #{yarn_flags}")
-    end
+    prefix = task.name.split(/#|webpacker:/).first
+    Rake::Task["#{prefix}shakapacker:yarn_install"].invoke
   end
 end
diff --git a/lib/webpacker.rb b/lib/webpacker.rb
index 5979133d4..68b873a6c 100644
--- a/lib/webpacker.rb
+++ b/lib/webpacker.rb
@@ -1,48 +1,4 @@
-require "active_support/core_ext/module/attribute_accessors"
-require "active_support/core_ext/string/inquiry"
-require "active_support/logger"
-require "active_support/tagged_logging"
+# This file exists for backward compatibility
+require "shakapacker"
 
-module Webpacker
-  extend self
-
-  DEFAULT_ENV = "production".freeze
-
-  def instance=(instance)
-    @instance = instance
-  end
-
-  def instance
-    @instance ||= Webpacker::Instance.new
-  end
-
-  def with_node_env(env)
-    original = ENV["NODE_ENV"]
-    ENV["NODE_ENV"] = env
-    yield
-  ensure
-    ENV["NODE_ENV"] = original
-  end
-
-  def ensure_log_goes_to_stdout
-    old_logger = Webpacker.logger
-    Webpacker.logger = Logger.new(STDOUT)
-    yield
-  ensure
-    Webpacker.logger = old_logger
-  end
-
-  delegate :logger, :logger=, :env, :inlining_css?, to: :instance
-  delegate :config, :compiler, :manifest, :commands, :dev_server, to: :instance
-  delegate :bootstrap, :clean, :clobber, :compile, to: :commands
-end
-
-require "webpacker/instance"
-require "webpacker/env"
-require "webpacker/configuration"
-require "webpacker/manifest"
-require "webpacker/compiler"
-require "webpacker/commands"
-require "webpacker/dev_server"
-
-require "webpacker/railtie" if defined?(Rails)
+Shakapacker.puts_deprecation_message(Shakapacker::DEPRECATION_MESSAGE)
diff --git a/lib/webpacker/dev_server_runner.rb b/lib/webpacker/dev_server_runner.rb
index 0ce83623c..e3430571f 100644
--- a/lib/webpacker/dev_server_runner.rb
+++ b/lib/webpacker/dev_server_runner.rb
@@ -1,96 +1,9 @@
-require "shellwords"
-require "socket"
-require "webpacker/configuration"
-require "webpacker/dev_server"
-require "webpacker/runner"
-
-module Webpacker
-  class DevServerRunner < Webpacker::Runner
-    def run
-      load_config
-      detect_unsupported_switches!
-      detect_port!
-      execute_cmd
-    end
-
-    private
-
-      def load_config
-        app_root = Pathname.new(@app_path)
-
-        @config = Configuration.new(
-          root_path: app_root,
-          config_path: Pathname.new(@webpacker_config),
-          env: ENV["RAILS_ENV"]
-        )
-
-        dev_server = DevServer.new(@config)
-
-        @hostname          = dev_server.host
-        @port              = dev_server.port
-        @pretty            = dev_server.pretty?
-        @https             = dev_server.https?
-        @hot               = dev_server.hmr?
-
-      rescue Errno::ENOENT, NoMethodError
-        $stdout.puts "webpack dev_server configuration not found in #{@config.config_path}[#{ENV["RAILS_ENV"]}]."
-        $stdout.puts "Please run bundle exec rails webpacker:install to install Webpacker"
-        exit!
-      end
-
-      UNSUPPORTED_SWITCHES = %w[--host --port]
-      private_constant :UNSUPPORTED_SWITCHES
-      def detect_unsupported_switches!
-        unsupported_switches = UNSUPPORTED_SWITCHES & @argv
-        if unsupported_switches.any?
-          $stdout.puts "The following CLI switches are not supported by Webpacker: #{unsupported_switches.join(' ')}. Please edit your command and try again."
-          exit!
-        end
-
-        if @argv.include?("--https") && !@https
-          $stdout.puts "Please set https: true in webpacker.yml to use the --https command line flag."
-          exit!
-        end
-      end
-
-      def detect_port!
-        server = TCPServer.new(@hostname, @port)
-        server.close
-
-      rescue Errno::EADDRINUSE
-        $stdout.puts "Another program is running on port #{@port}. Set a new port in #{@config.config_path} for dev_server"
-        exit!
-      end
-
-      def execute_cmd
-        env = Webpacker::Compiler.env
-        env["WEBPACKER_CONFIG"] = @webpacker_config
-        env["WEBPACK_SERVE"] = "true"
-
-        cmd = if node_modules_bin_exist?
-          ["#{@node_modules_bin_path}/webpack", "serve"]
-        else
-          ["yarn", "webpack", "serve"]
-        end
-
-        if @argv.include?("--debug-webpacker")
-          cmd = [ "node", "--inspect-brk", "--trace-warnings" ] + cmd
-          @argv.delete "--debug-webpacker"
-        end
-
-        cmd += ["--config", @webpack_config]
-        cmd += ["--progress", "--color"] if @pretty
-
-        cmd += ["--hot"] if @hot
-        cmd += @argv
-
-        Dir.chdir(@app_path) do
-          Kernel.exec env, *cmd
-        end
-      end
-
-      def node_modules_bin_exist?
-        File.exist?("#{@node_modules_bin_path}/webpack-dev-server")
-      end
-  end
-end
+# This file exists for backward compatibility
+require "shakapacker/dev_server_runner"
+
+Shakapacker.puts_deprecation_message(
+  Shakapacker.short_deprecation_message(
+    "bin/webpacker-dev-server",
+    "bin/shakapacker-dev-server"
+  )
+)
diff --git a/lib/webpacker/railtie.rb b/lib/webpacker/railtie.rb
deleted file mode 100644
index 6166001be..000000000
--- a/lib/webpacker/railtie.rb
+++ /dev/null
@@ -1,70 +0,0 @@
-require "rails/railtie"
-
-require "webpacker/helper"
-require "webpacker/dev_server_proxy"
-require "webpacker/version_checker"
-
-class Webpacker::Engine < ::Rails::Engine
-  # Allows Webpacker config values to be set via Rails env config files
-  config.webpacker = ActiveSupport::OrderedOptions.new
-
-  initializer "webpacker.version_checker" do
-    if File.exist?(Webpacker::VersionChecker::NodePackageVersion.package_json_path)
-      Webpacker::VersionChecker.build.raise_if_gem_and_node_package_versions_differ
-    end
-  end
-
-  initializer "webpacker.proxy" do |app|
-    if (Webpacker.config.dev_server.present? rescue nil)
-      app.middleware.insert_before 0,
-        Rails::VERSION::MAJOR >= 5 ?
-          Webpacker::DevServerProxy : "Webpacker::DevServerProxy", ssl_verify_none: true
-    end
-  end
-
-  initializer "webpacker.helper" do
-    ActiveSupport.on_load :action_controller do
-      ActionController::Base.helper Webpacker::Helper
-    end
-
-    ActiveSupport.on_load :action_view do
-      include Webpacker::Helper
-    end
-  end
-
-  initializer "webpacker.logger" do
-    config.after_initialize do
-      if ::Rails.logger.respond_to?(:tagged)
-        Webpacker.logger = ::Rails.logger
-      else
-        Webpacker.logger = ActiveSupport::TaggedLogging.new(::Rails.logger)
-      end
-    end
-  end
-
-  initializer "webpacker.bootstrap" do
-    if defined?(Rails::Server) || defined?(Rails::Console)
-      Webpacker.bootstrap
-      if defined?(Spring)
-        require "spring/watcher"
-        Spring.after_fork { Webpacker.bootstrap }
-        Spring.watch(Webpacker.config.config_path)
-      end
-    end
-  end
-
-  initializer "webpacker.set_source" do |app|
-    if Webpacker.config.config_path.exist?
-      app.config.javascript_path = Webpacker.config.source_path.relative_path_from(Rails.root.join("app")).to_s
-    end
-  end
-
-  initializer "webpacker.remove_app_packs_from_the_autoload_paths" do
-    Rails.application.config.before_initialize do
-      if Webpacker.config.config_path.exist?
-        source_path = Webpacker.config.source_path.to_s
-        ActiveSupport::Dependencies.autoload_paths.delete(source_path)
-      end
-    end
-  end
-end
diff --git a/lib/webpacker/runner.rb b/lib/webpacker/runner.rb
deleted file mode 100644
index 3adaedd70..000000000
--- a/lib/webpacker/runner.rb
+++ /dev/null
@@ -1,23 +0,0 @@
-module Webpacker
-  class Runner
-    def self.run(argv)
-      $stdout.sync = true
-      ENV["NODE_ENV"] ||= (ENV["RAILS_ENV"] == "production") ? "production" : "development"
-      new(argv).run
-    end
-
-    def initialize(argv)
-      @argv = argv
-
-      @app_path              = File.expand_path(".", Dir.pwd)
-      @node_modules_bin_path = ENV["WEBPACKER_NODE_MODULES_BIN_PATH"] || `yarn bin`.chomp
-      @webpack_config        = File.join(@app_path, "config/webpack/webpack.config.js")
-      @webpacker_config      = ENV["WEBPACKER_CONFIG"] || File.join(@app_path, "config/webpacker.yml")
-
-      unless File.exist?(@webpack_config)
-        $stderr.puts "webpack config #{@webpack_config} not found, please run 'bundle exec rails webpacker:install' to install Webpacker with default configs or add the missing config file for your custom environment."
-        exit!
-      end
-    end
-  end
-end
diff --git a/lib/webpacker/webpack_runner.rb b/lib/webpacker/webpack_runner.rb
index f72a7ca7e..cd2f31e83 100644
--- a/lib/webpacker/webpack_runner.rb
+++ b/lib/webpacker/webpack_runner.rb
@@ -1,58 +1,9 @@
-require "shellwords"
-require "webpacker/runner"
-
-module Webpacker
-  class WebpackRunner < Webpacker::Runner
-    WEBPACK_COMMANDS = [
-      "help",
-      "h",
-      "--help",
-      "-h",
-      "version",
-      "v",
-      "--version",
-      "-v",
-      "info",
-      "i"
-    ].freeze
-
-    def run
-      env = Webpacker::Compiler.env
-      env["WEBPACKER_CONFIG"] = @webpacker_config
-
-      cmd = if node_modules_bin_exist?
-        ["#{@node_modules_bin_path}/webpack"]
-      else
-        ["yarn", "webpack"]
-      end
-
-      if @argv.delete "--debug-webpacker"
-        cmd = ["node", "--inspect-brk"] + cmd
-      end
-
-      if @argv.delete "--trace-deprecation"
-        cmd = ["node", "--trace-deprecation"] + cmd
-      end
-
-      if @argv.delete "--no-deprecation"
-        cmd = ["node", "--no-deprecation"] + cmd
-      end
-
-      # Webpack commands are not compatible with --config option.
-      if (@argv & WEBPACK_COMMANDS).empty?
-        cmd += ["--config", @webpack_config]
-      end
-
-      cmd += @argv
-
-      Dir.chdir(@app_path) do
-        Kernel.exec env, *cmd
-      end
-    end
-
-    private
-      def node_modules_bin_exist?
-        File.exist?("#{@node_modules_bin_path}/webpack")
-      end
-  end
-end
+# This file exists for backward compatibility
+require "shakapacker/webpack_runner"
+
+Shakapacker.puts_deprecation_message(
+  Shakapacker.short_deprecation_message(
+    "bin/webpacker",
+    "bin/shakapacker"
+  )
+)
diff --git a/package.json b/package.json
index 1787b9db3..900291a0b 100644
--- a/package.json
+++ b/package.json
@@ -5,7 +5,7 @@
   "main": "package/index.js",
   "files": [
     "package",
-    "lib/install/config/webpacker.yml"
+    "lib/install/config/shakapacker.yml"
   ],
   "engines": {
     "node": "^12.13.0 || ^14 || >=16",
diff --git a/package/__tests__/config-bc.js b/package/__tests__/config-bc.js
new file mode 100644
index 000000000..a71508e84
--- /dev/null
+++ b/package/__tests__/config-bc.js
@@ -0,0 +1,27 @@
+/* global test expect, describe */
+const { resolve } = require('path')
+const { chdirWebpackerTestApp, resetEnv } = require('../utils/helpers')
+
+const rootPath = process.cwd()
+chdirWebpackerTestApp()
+
+const config = require('../config')
+
+describe('Backward Compatibility - Config', () => { 
+  beforeEach(() => jest.resetModules() && resetEnv())
+  afterAll(() => process.chdir(rootPath))
+
+  test('x public path with asset host', () => {
+    process.env.RAILS_ENV = 'development'
+    process.env.WEBPACKER_ASSET_HOST = 'http://foo.com/'
+    const config = require('../config')
+
+    expect(config.publicPath).toEqual('http://foo.com/packs/')
+  })
+
+  test('x should allow overriding manifestPath', () => {
+    process.env.WEBPACKER_CONFIG = 'config/webpacker_manifest_path.yml'
+    const config = require('../config')
+    expect(config.manifestPath).toEqual(resolve('app/packs/manifest.json'))
+  })
+})
diff --git a/package/__tests__/config.js b/package/__tests__/config.js
index a1a3b9fb8..54256e433 100644
--- a/package/__tests__/config.js
+++ b/package/__tests__/config.js
@@ -1,15 +1,16 @@
 /* global test expect, describe */
 
-const { chdirCwd, chdirTestApp, resetEnv } = require('../utils/helpers')
+const { chdirTestApp, resetEnv } = require('../utils/helpers')
 const { resolve } = require('path')
 
+const rootPath = process.cwd()
 chdirTestApp()
 
 const config = require('../config')
 
 describe('Config', () => {
   beforeEach(() => jest.resetModules() && resetEnv())
-  afterAll(chdirCwd)
+  afterAll(() => process.chdir(rootPath))
 
   test('public path', () => {
     process.env.RAILS_ENV = 'development'
@@ -19,7 +20,7 @@ describe('Config', () => {
 
   test('public path with asset host', () => {
     process.env.RAILS_ENV = 'development'
-    process.env.WEBPACKER_ASSET_HOST = 'http://foo.com/'
+    process.env.SHAKAPACKER_ASSET_HOST = 'http://foo.com/'
     const config = require('../config')
     expect(config.publicPath).toEqual('http://foo.com/packs/')
   })
@@ -38,7 +39,7 @@ describe('Config', () => {
   })
 
   test('should allow overriding manifestPath', () => {
-    process.env.WEBPACKER_CONFIG = 'config/webpacker_manifest_path.yml'
+    process.env.SHAKAPACKER_CONFIG = 'config/shakapacker_manifest_path.yml'
     const config = require('../config')
     expect(config.manifestPath).toEqual(resolve('app/javascript/manifest.json'))
   })
diff --git a/package/__tests__/dev_server-bc.js b/package/__tests__/dev_server-bc.js
new file mode 100644
index 000000000..fa94a4ff9
--- /dev/null
+++ b/package/__tests__/dev_server-bc.js
@@ -0,0 +1,46 @@
+/* global test expect, describe */
+
+const { chdirWebpackerTestApp } = require('../utils/helpers')
+
+const rootPath = process.cwd()
+chdirWebpackerTestApp()
+
+describe('Backward Compatibility - DevServer', () => {
+  beforeEach(() => jest.resetModules())
+  afterAll(() => process.chdir(rootPath))
+
+  test('with NODE_ENV and RAILS_ENV set to development', () => {
+    process.env.NODE_ENV = 'development'
+    process.env.RAILS_ENV = 'development'
+    process.env.WEBPACKER_DEV_SERVER_HOST = '0.0.0.0'
+    process.env.WEBPACKER_DEV_SERVER_PORT = 5000
+    process.env.WEBPACKER_DEV_SERVER_DISABLE_HOST_CHECK = false
+
+    const devServer = require('../dev_server')
+    expect(devServer).toBeDefined()
+    expect(devServer.host).toEqual('0.0.0.0')
+    expect(devServer.port).toEqual('5000')
+    expect(devServer.disable_host_check).toBe(false)
+  })
+
+  test('with custom env prefix', () => {
+    const config = require('../config')
+    config.dev_server.env_prefix = 'TEST_WEBPACKER_DEV_SERVER'
+
+    process.env.NODE_ENV = 'development'
+    process.env.RAILS_ENV = 'development'
+    process.env.TEST_WEBPACKER_DEV_SERVER_HOST = '0.0.0.0'
+    process.env.TEST_WEBPACKER_DEV_SERVER_PORT = 5000
+
+    const devServer = require('../dev_server')
+    expect(devServer).toBeDefined()
+    expect(devServer.host).toEqual('0.0.0.0')
+    expect(devServer.port).toEqual('5000')
+  })
+
+  test('with NODE_ENV and RAILS_ENV set to production', () => {
+    process.env.RAILS_ENV = 'production'
+    process.env.NODE_ENV = 'production'
+    expect(require('../dev_server')).toEqual({})
+  })
+})
diff --git a/package/__tests__/dev_server.js b/package/__tests__/dev_server.js
index d20cc93d4..cb930198c 100644
--- a/package/__tests__/dev_server.js
+++ b/package/__tests__/dev_server.js
@@ -1,19 +1,20 @@
 /* global test expect, describe */
 
-const { chdirTestApp, chdirCwd } = require('../utils/helpers')
+const { chdirTestApp } = require('../utils/helpers')
 
+const rootPath = process.cwd()
 chdirTestApp()
 
 describe('DevServer', () => {
   beforeEach(() => jest.resetModules())
-  afterAll(chdirCwd)
+  afterAll(() => process.chdir(rootPath))
 
   test('with NODE_ENV and RAILS_ENV set to development', () => {
     process.env.NODE_ENV = 'development'
     process.env.RAILS_ENV = 'development'
-    process.env.WEBPACKER_DEV_SERVER_HOST = '0.0.0.0'
-    process.env.WEBPACKER_DEV_SERVER_PORT = 5000
-    process.env.WEBPACKER_DEV_SERVER_DISABLE_HOST_CHECK = false
+    process.env.SHAKAPACKER_DEV_SERVER_HOST = '0.0.0.0'
+    process.env.SHAKAPACKER_DEV_SERVER_PORT = 5000
+    process.env.SHAKAPACKER_DEV_SERVER_DISABLE_HOST_CHECK = false
 
     const devServer = require('../dev_server')
     expect(devServer).toBeDefined()
@@ -24,12 +25,12 @@ describe('DevServer', () => {
 
   test('with custom env prefix', () => {
     const config = require('../config')
-    config.dev_server.env_prefix = 'TEST_WEBPACKER_DEV_SERVER'
+    config.dev_server.env_prefix = 'TEST_SHAKAPACKER_DEV_SERVER'
 
     process.env.NODE_ENV = 'development'
     process.env.RAILS_ENV = 'development'
-    process.env.TEST_WEBPACKER_DEV_SERVER_HOST = '0.0.0.0'
-    process.env.TEST_WEBPACKER_DEV_SERVER_PORT = 5000
+    process.env.TEST_SHAKAPACKER_DEV_SERVER_HOST = '0.0.0.0'
+    process.env.TEST_SHAKAPACKER_DEV_SERVER_PORT = 5000
 
     const devServer = require('../dev_server')
     expect(devServer).toBeDefined()
diff --git a/package/__tests__/development-bc.js b/package/__tests__/development-bc.js
new file mode 100644
index 000000000..4bf7fe126
--- /dev/null
+++ b/package/__tests__/development-bc.js
@@ -0,0 +1,37 @@
+/* test expect, describe, afterAll, beforeEach */
+
+const { resolve } = require('path')
+const { chdirWebpackerTestApp, resetEnv } = require('../utils/helpers')
+
+const rootPath = process.cwd()
+chdirWebpackerTestApp()
+
+describe('Backward Compatibility - Development environment', () => {
+  beforeEach(() => jest.resetModules() && resetEnv())
+  afterAll(() => process.chdir(rootPath))
+
+  describe('webpackConfig', () => {
+    beforeEach(() => jest.resetModules())
+
+    test('should use development config and environment including devServer if WEBPACK_SERVE', () => {
+      process.env.RAILS_ENV = 'development'
+      process.env.NODE_ENV = 'development'
+      process.env.WEBPACK_SERVE = 'true'
+      const { webpackConfig } = require('../index')
+
+      expect(webpackConfig.output.path).toEqual(resolve('public', 'packs'))
+      expect(webpackConfig.output.publicPath).toEqual('/packs/')
+    })
+
+    test('should use development config and environment if WEBPACK_SERVE', () => {
+      process.env.RAILS_ENV = 'development'
+      process.env.NODE_ENV = 'development'
+      process.env.WEBPACK_SERVE = undefined
+      const { webpackConfig } = require('../index')
+
+      expect(webpackConfig.output.path).toEqual(resolve('public', 'packs'))
+      expect(webpackConfig.output.publicPath).toEqual('/packs/')
+      expect(webpackConfig.devServer).toEqual(undefined)
+    })
+  })
+})
diff --git a/package/__tests__/development.js b/package/__tests__/development.js
index 22a7491a8..0f3dac262 100644
--- a/package/__tests__/development.js
+++ b/package/__tests__/development.js
@@ -1,12 +1,14 @@
 /* test expect, describe, afterAll, beforeEach */
 
 const { resolve } = require('path')
-const { chdirTestApp, chdirCwd } = require('../utils/helpers')
+const { chdirTestApp, resetEnv } = require('../utils/helpers')
 
+const rootPath = process.cwd()
 chdirTestApp()
 
 describe('Development environment', () => {
-  afterAll(chdirCwd)
+  beforeEach(() => jest.resetModules() && resetEnv())
+  afterAll(() => process.chdir(rootPath))
 
   describe('webpackConfig', () => {
     beforeEach(() => jest.resetModules())
diff --git a/package/__tests__/env-bc.js b/package/__tests__/env-bc.js
new file mode 100644
index 000000000..8fcefc4cb
--- /dev/null
+++ b/package/__tests__/env-bc.js
@@ -0,0 +1,59 @@
+/* global test expect, describe */
+
+const { chdirWebpackerTestApp, resetEnv } = require('../utils/helpers')
+
+const rootPath = process.cwd()
+chdirWebpackerTestApp()
+
+describe('Backward Compatibility - Env', () => {
+  beforeEach(() => jest.resetModules() && resetEnv())
+  afterAll(() => process.chdir(rootPath))
+
+  test('with NODE_ENV and RAILS_ENV set to development', () => {
+    process.env.RAILS_ENV = 'development'
+    process.env.NODE_ENV = 'development'
+    expect(require('../env')).toEqual({
+      railsEnv: 'development',
+      nodeEnv: 'development',
+      isProduction: false,
+      isDevelopment: true,
+      runningWebpackDevServer: false
+    })
+  })
+
+  test('with undefined NODE_ENV and RAILS_ENV set to development', () => {
+    process.env.RAILS_ENV = 'development'
+    delete process.env.NODE_ENV
+    expect(require('../env')).toEqual({
+      railsEnv: 'development',
+      nodeEnv: 'production',
+      isProduction: true,
+      isDevelopment: false,
+      runningWebpackDevServer: false
+    })
+  })
+
+  test('with undefined NODE_ENV and RAILS_ENV', () => {
+    delete process.env.NODE_ENV
+    delete process.env.RAILS_ENV
+    expect(require('../env')).toEqual({
+      railsEnv: 'production',
+      nodeEnv: 'production',
+      isProduction: true,
+      isDevelopment: false,
+      runningWebpackDevServer: false
+    })
+  })
+
+  test('with a non-standard environment', () => {
+    process.env.RAILS_ENV = 'staging'
+    process.env.NODE_ENV = 'staging'
+    expect(require('../env')).toEqual({
+      railsEnv: 'staging',
+      nodeEnv: 'production',
+      isProduction: true,
+      isDevelopment: false,
+      runningWebpackDevServer: false
+    })
+  })
+})
diff --git a/package/__tests__/env.js b/package/__tests__/env.js
index e31d80d18..d399a21d7 100644
--- a/package/__tests__/env.js
+++ b/package/__tests__/env.js
@@ -1,12 +1,13 @@
 /* global test expect, describe */
 
-const { chdirTestApp, chdirCwd } = require('../utils/helpers')
+const { chdirTestApp } = require('../utils/helpers')
 
+const rootPath = process.cwd()
 chdirTestApp()
 
 describe('Env', () => {
   beforeEach(() => jest.resetModules())
-  afterAll(chdirCwd)
+  afterAll(() => process.chdir(rootPath))
 
   test('with NODE_ENV and RAILS_ENV set to development', () => {
     process.env.RAILS_ENV = 'development'
diff --git a/package/__tests__/production-bc.js b/package/__tests__/production-bc.js
new file mode 100644
index 000000000..a6c3450de
--- /dev/null
+++ b/package/__tests__/production-bc.js
@@ -0,0 +1,30 @@
+/* test expect, describe, afterAll, beforeEach */
+
+const { resolve } = require('path')
+const { chdirWebpackerTestApp } = require('../utils/helpers')
+
+const rootPath = process.cwd()
+chdirWebpackerTestApp()
+
+describe('Backward Compatibility - Production environment', () => {
+  afterAll(() => process.chdir(rootPath))
+
+  describe('webpackConfig', () => {
+    beforeEach(() => jest.resetModules())
+
+    test('should use production config and environment', () => {
+      process.env.RAILS_ENV = 'production'
+      process.env.NODE_ENV = 'production'
+
+      const { webpackConfig } = require('../index')
+
+      expect(webpackConfig.output.path).toEqual(resolve('public', 'packs'))
+      expect(webpackConfig.output.publicPath).toEqual('/packs/')
+
+      expect(webpackConfig).toMatchObject({
+        devtool: 'source-map',
+        stats: 'normal'
+      })
+    })
+  })
+})
diff --git a/package/__tests__/production.js b/package/__tests__/production.js
index ec23b9731..85803e1ff 100644
--- a/package/__tests__/production.js
+++ b/package/__tests__/production.js
@@ -3,10 +3,11 @@
 const { resolve } = require('path')
 const { chdirTestApp, chdirCwd } = require('../utils/helpers')
 
+const rootPath = process.cwd()
 chdirTestApp()
 
 describe('Production environment', () => {
-  afterAll(chdirCwd)
+  afterAll(() => process.chdir(rootPath))
 
   describe('webpackConfig', () => {
     beforeEach(() => jest.resetModules())
diff --git a/package/__tests__/staging-bc.js b/package/__tests__/staging-bc.js
new file mode 100644
index 000000000..af5f43666
--- /dev/null
+++ b/package/__tests__/staging-bc.js
@@ -0,0 +1,31 @@
+/* test expect, describe, afterAll, beforeEach */
+
+const { resolve } = require('path')
+const { chdirWebpackerTestApp } = require('../utils/helpers')
+
+const rootPath = process.cwd()
+chdirWebpackerTestApp()
+
+describe('Backward Compatibility - Custom environment', () => {
+  afterAll(() => process.chdir(rootPath))
+
+  describe('webpackConfig', () => {
+    beforeEach(() => jest.resetModules())
+
+    test('should use staging config and default production environment', () => {
+      process.env.RAILS_ENV = 'staging'
+      delete process.env.NODE_ENV
+
+      const { webpackConfig } = require('../index')
+
+      expect(webpackConfig.output.path).toEqual(
+        resolve('public', 'packs-staging')
+      )
+      expect(webpackConfig.output.publicPath).toEqual('/packs-staging/')
+      expect(webpackConfig).toMatchObject({
+        devtool: 'source-map',
+        stats: 'normal'
+      })
+    })
+  })
+})
diff --git a/package/__tests__/staging.js b/package/__tests__/staging.js
index c3034a703..d80345b0e 100644
--- a/package/__tests__/staging.js
+++ b/package/__tests__/staging.js
@@ -1,12 +1,13 @@
 /* test expect, describe, afterAll, beforeEach */
 
 const { resolve } = require('path')
-const { chdirTestApp, chdirCwd } = require('../utils/helpers')
+const { chdirTestApp } = require('../utils/helpers')
 
+const rootPath = process.cwd()
 chdirTestApp()
 
 describe('Custom environment', () => {
-  afterAll(chdirCwd)
+  afterAll(() => process.chdir(rootPath))
 
   describe('webpackConfig', () => {
     beforeEach(() => jest.resetModules())
diff --git a/package/__tests__/test-bc.js b/package/__tests__/test-bc.js
new file mode 100644
index 000000000..da7ac86a0
--- /dev/null
+++ b/package/__tests__/test-bc.js
@@ -0,0 +1,26 @@
+/* test expect, describe, afterAll, beforeEach */
+
+const { resolve } = require('path')
+const { chdirWebpackerTestApp } = require('../utils/helpers')
+
+const rootPath = process.cwd()
+chdirWebpackerTestApp()
+
+describe('Backward Compatibility - Test environment', () => {
+  afterAll(() => process.chdir(rootPath))
+
+  describe('toWebpackConfig', () => {
+    beforeEach(() => jest.resetModules())
+
+    test('should use test config and production environment', () => {
+      process.env.RAILS_ENV = 'test'
+      process.env.NODE_ENV = 'test'
+
+      const { webpackConfig } = require('../index')
+
+      expect(webpackConfig.output.path).toEqual(resolve('public', 'packs-test'))
+      expect(webpackConfig.output.publicPath).toEqual('/packs-test/')
+      expect(webpackConfig.devServer).toEqual(undefined)
+    })
+  })
+})
diff --git a/package/__tests__/test.js b/package/__tests__/test.js
index 0584fdc82..1440717f9 100644
--- a/package/__tests__/test.js
+++ b/package/__tests__/test.js
@@ -1,12 +1,13 @@
 /* test expect, describe, afterAll, beforeEach */
 
 const { resolve } = require('path')
-const { chdirTestApp, chdirCwd } = require('../utils/helpers')
+const { chdirTestApp } = require('../utils/helpers')
 
+const rootPath = process.cwd()
 chdirTestApp()
 
 describe('Test environment', () => {
-  afterAll(chdirCwd)
+  afterAll(() => process.chdir(rootPath))
 
   describe('toWebpackConfig', () => {
     beforeEach(() => jest.resetModules())
diff --git a/package/config.js b/package/config.js
index fc01cc8bc..cf9e13056 100644
--- a/package/config.js
+++ b/package/config.js
@@ -2,11 +2,14 @@ const { resolve } = require('path')
 const { load } = require('js-yaml')
 const { readFileSync } = require('fs')
 const { merge } = require('webpack-merge')
-const { ensureTrailingSlash } = require('./utils/helpers')
+const {
+  ensureTrailingSlash,
+  setShakapackerEnvVariablesForBackwardCompatibility
+} = require('./utils/helpers')
 const { railsEnv } = require('./env')
 const configPath = require('./configPath')
 
-const defaultConfigPath = require.resolve('../lib/install/config/webpacker.yml')
+const defaultConfigPath = require.resolve('../config/shakapacker.yml')
 
 const getDefaultConfig = () => {
   const defaultConfig = load(readFileSync(defaultConfigPath), 'utf8')
@@ -22,7 +25,8 @@ config.outputPath = resolve(config.public_root_path, config.public_output_path)
 // Ensure that the publicPath includes our asset host so dynamic imports
 // (code-splitting chunks and static assets) load from the CDN instead of a relative path.
 const getPublicPath = () => {
-  const rootUrl = ensureTrailingSlash(process.env.WEBPACKER_ASSET_HOST || '/')
+  setShakapackerEnvVariablesForBackwardCompatibility()
+  const rootUrl = ensureTrailingSlash(process.env.SHAKAPACKER_ASSET_HOST || '/')
   return `${rootUrl}${config.public_output_path}/`
 }
 
diff --git a/package/configPath.js b/package/configPath.js
index fc0b44236..f3dbd2f70 100644
--- a/package/configPath.js
+++ b/package/configPath.js
@@ -1,3 +1,19 @@
+const fs = require('fs')
 const { resolve } = require('path')
+const { setShakapackerEnvVariablesForBackwardCompatibility } = require('./utils/helpers')
 
-module.exports = process.env.WEBPACKER_CONFIG || resolve('config', 'webpacker.yml')
+setShakapackerEnvVariablesForBackwardCompatibility()
+
+// For backward compatibility
+const resolveToPhysicalFilePath = () => {
+  const shakapackerConfigPath = resolve('config', 'shakapacker.yml')
+  const webpackerConfigPath = resolve('config', 'webpacker.yml')
+
+  if (fs.existsSync(shakapackerConfigPath)) return shakapackerConfigPath
+  if (fs.existsSync(webpackerConfigPath)) return webpackerConfigPath
+
+  // If neither of files exist, try to resolve to shakapacker.yml to get more relevant error
+  return shakapackerConfigPath
+}
+
+module.exports = process.env.SHAKAPACKER_CONFIG || resolveToPhysicalFilePath()
diff --git a/package/dev_server.js b/package/dev_server.js
index b482c8026..ae9f9a7b7 100644
--- a/package/dev_server.js
+++ b/package/dev_server.js
@@ -1,20 +1,66 @@
 const { isBoolean } = require('./utils/helpers')
 const config = require('./config')
+const { outputPath: contentBase, publicPath } = require('./config')
+const { isDevelopment } = require('./env')
 
-const fetch = (key) => {
+const fetchFromEnv = (key) => {
   const value = process.env[key]
   return isBoolean(value) ? JSON.parse(value) : value
 }
 
-const devServerConfig = config.dev_server
+let devServer = {}
 
-if (devServerConfig) {
-  const envPrefix = config.dev_server.env_prefix || 'WEBPACKER_DEV_SERVER'
+if (isDevelopment) {
+  const devServerFromConfigFile = config.dev_server
 
-  Object.keys(devServerConfig).forEach((key) => {
-    const envValue = fetch(`${envPrefix}_${key.toUpperCase()}`)
-    if (envValue !== undefined) devServerConfig[key] = envValue
+  if (devServerFromConfigFile) {
+    const envPrefix = devServerFromConfigFile.env_prefix || 'SHAKAPACKER_DEV_SERVER'
+
+    Object.keys(devServerFromConfigFile).forEach((key) => {
+      const envValue = fetchFromEnv(`${envPrefix}_${key.toUpperCase()}`)
+      if (envValue !== undefined) devServerFromConfigFile[key] = envValue
+    })
+  }
+
+  const liveReload = devServerFromConfigFile.live_reload !== undefined ? devServerFromConfigFile.live_reload : !devServerFromConfigFile.hmr
+
+  devServer = {
+    devMiddleware: {
+      publicPath
+    },
+    liveReload,
+    historyApiFallback: { disableDotRule: true },
+    static: {
+      publicPath: contentBase
+    }
+  }
+
+  if (devServerFromConfigFile.static) {
+    devServer.static = { ...devServer.static, ...devServerFromConfigFile.static }
+  }
+
+  if (devServerFromConfigFile.client) {
+    devServer.client = devServerFromConfigFile.client
+  }
+
+  const webpackSpecificKeysMapToCamelCase = {
+    allowed_hosts: 'allowedHosts',
+    magic_html: 'magicHtml',
+    on_after_setup_middleware: 'onAfterSetupMiddleware',
+    on_before_setup_middleware: 'onBeforeSetupMiddleware',
+    on_listening: 'onListening',
+    setup_exit_signals: 'setupExitSignals',
+    setup_middlewares: 'setupMiddlewares',
+    watch_files: 'watchFiles',
+    web_socket_server: 'webSocketServer'
+  }
+
+  // Copying all the entries by only converting webpack specific keys from
+  // snake_case to camelCase. Any other entries are copied identically.
+  Object.keys(devServerFromConfigFile).forEach((rubyKey) => {
+    const webpackKey = webpackSpecificKeysMapToCamelCase[rubyKey] ? webpackSpecificKeysMapToCamelCase[rubyKey] : rubyKey
+    devServer[webpackKey] = devServer[webpackKey] || devServerFromConfigFile[rubyKey]
   })
 }
 
-module.exports = devServerConfig || {}
+module.exports = devServer
diff --git a/package/environments/__tests__/base-bc.js b/package/environments/__tests__/base-bc.js
new file mode 100644
index 000000000..22a1eaeab
--- /dev/null
+++ b/package/environments/__tests__/base-bc.js
@@ -0,0 +1,107 @@
+/* global test expect, describe, afterAll, beforeEach */
+
+// environment.js expects to find config/webapacker.yml and resolved modules from
+// the root of a Rails project
+
+const { resetEnv, chdirWebpackerTestApp } = require('../../utils/helpers')
+
+const rootPath = process.cwd()
+chdirWebpackerTestApp()
+
+const { resolve } = require('path')
+
+const baseConfig = require('../base')
+const config = require("../../config");
+
+describe('Base config', () => {
+  beforeEach(() => jest.resetModules() && resetEnv())
+  afterAll(() => process.chdir(rootPath))
+
+  describe('config', () => {
+    test('should return entry', () => {
+      expect(baseConfig.entry.application).toEqual(
+        resolve('app', 'packs', 'entrypoints', 'application.js')
+      )
+    })
+
+    test('should return false for css_extract_ignore_order_warnings when using default config', () => {
+      expect(config.css_extract_ignore_order_warnings).toEqual(false)
+    })
+
+    test('should return true for css_extract_ignore_order_warnings when configured', () => {
+      process.env.WEBPACKER_CONFIG = 'config/webpacker_css_extract_ignore_order_warnings.yml'
+      const config = require("../../config");
+
+      expect(config.css_extract_ignore_order_warnings).toEqual(true)
+    })
+
+    test('should return only 2 entry points with config.nested_entries == false', () => {
+      expect(config.nested_entries).toEqual(false)
+
+      expect(baseConfig.entry.multi_entry.sort()).toEqual([
+        resolve('app', 'packs', 'entrypoints', 'multi_entry.css'),
+        resolve('app', 'packs', 'entrypoints', 'multi_entry.js')
+      ])
+      expect(baseConfig.entry['generated/something']).toEqual(undefined)
+    })
+
+    test('should returns top level and nested entry points with config.nested_entries == true', () => {
+      process.env.WEBPACKER_CONFIG = 'config/webpacker_nested_entries.yml'
+      const config = require("../../config");
+      const baseConfig = require('../base')
+
+      expect(config.nested_entries).toEqual(true)
+
+      expect(baseConfig.entry.application).toEqual(
+        resolve('app', 'packs', 'entrypoints', 'application.js')
+      )
+      expect(baseConfig.entry.multi_entry.sort()).toEqual([
+        resolve('app', 'packs', 'entrypoints', 'multi_entry.css'),
+        resolve('app', 'packs', 'entrypoints', 'multi_entry.js')
+      ])
+      expect(baseConfig.entry['generated/something']).toEqual(
+        resolve('app', 'packs', 'entrypoints', 'generated', 'something.js')
+      )
+    })
+
+    test('should return output', () => {
+      expect(baseConfig.output.filename).toEqual('js/[name].js')
+      expect(baseConfig.output.chunkFilename).toEqual(
+        'js/[name].chunk.js'
+      )
+    })
+
+    test('should return default loader rules for each file in config/loaders', () => {
+      const rules = require('../../rules')
+
+      const defaultRules = Object.keys(rules)
+      const configRules = baseConfig.module.rules
+
+      expect(defaultRules.length).toEqual(3)
+      expect(configRules.length).toEqual(3)
+    })
+
+    test('should return default plugins', () => {
+      expect(baseConfig.plugins.length).toEqual(2)
+    })
+
+    test('should return default resolveLoader', () => {
+      expect(baseConfig.resolveLoader.modules).toEqual(['node_modules'])
+    })
+
+    test('should return default resolve.modules with additions', () => {
+      expect(baseConfig.resolve.modules).toEqual([
+        resolve('app', 'packs'),
+        resolve('app/assets'),
+        resolve('/etc/yarn'),
+        resolve('some.config.js'),
+        resolve('app/elm'),
+        'node_modules'
+      ])
+    })
+
+    test('returns plugins property as Array', () => {
+      expect(baseConfig.plugins).toBeInstanceOf(Array)
+    })
+  })
+})
diff --git a/package/environments/__tests__/base.js b/package/environments/__tests__/base.js
index 57d8aa8da..d30127738 100644
--- a/package/environments/__tests__/base.js
+++ b/package/environments/__tests__/base.js
@@ -1,10 +1,11 @@
 /* global test expect, describe, afterAll, beforeEach */
 
-// environment.js expects to find config/webpacker.yml and resolved modules from
+// environment.js expects to find config/shakapacker.yml and resolved modules from
 // the root of a Rails project
 
 const { chdirTestApp, chdirCwd, resetEnv } = require('../../utils/helpers')
 
+const rootPath = process.cwd()
 chdirTestApp()
 
 const { resolve } = require('path')
@@ -14,8 +15,7 @@ const config = require("../../config");
 
 describe('Base config', () => {
   beforeEach(() => jest.resetModules() && resetEnv())
-
-  afterAll(chdirCwd)
+  afterAll(() => process.chdir(rootPath))
 
   describe('config', () => {
     test('should return entry', () => {
@@ -29,7 +29,7 @@ describe('Base config', () => {
     })
 
     test('should return true for css_extract_ignore_order_warnings when configured', () => {
-      process.env.WEBPACKER_CONFIG = 'config/webpacker_css_extract_ignore_order_warnings.yml'
+      process.env.SHAKAPACKER_CONFIG = 'config/shakapacker_css_extract_ignore_order_warnings.yml'
       const config = require("../../config");
 
       expect(config.css_extract_ignore_order_warnings).toEqual(true)
@@ -46,7 +46,7 @@ describe('Base config', () => {
     })
 
     test('should returns top level and nested entry points with config.nested_entries == true', () => {
-      process.env.WEBPACKER_CONFIG = 'config/webpacker_nested_entries.yml'
+      process.env.SHAKAPACKER_CONFIG = 'config/shakapacker_nested_entries.yml'
       const config = require("../../config");
       const baseConfig = require('../base')
 
diff --git a/package/environments/base.js b/package/environments/base.js
index f444280e0..6b11ef821 100644
--- a/package/environments/base.js
+++ b/package/environments/base.js
@@ -16,7 +16,7 @@ const getEntryObject = () => {
   const rootPath = join(config.source_path, config.source_entry_path)
   if (config.source_entry_path === '/' && config.nested_entries) {
     throw new Error(
-      "Your webpacker config specified using a source_entry_path of '/' with 'nested_entries' == " +
+      "Your shakapacker config specified using a source_entry_path of '/' with 'nested_entries' == " +
       "'true'. Doing this would result in packs for every one of your source files"
     )
   }
diff --git a/package/environments/development.js b/package/environments/development.js
index e7adc8eb1..97cfaadbf 100644
--- a/package/environments/development.js
+++ b/package/environments/development.js
@@ -1,45 +1,15 @@
 const { merge } = require('webpack-merge')
 
 const baseConfig = require('./base')
-const devServer = require('../dev_server')
+const devServerConfig = require('../dev_server')
 const { runningWebpackDevServer } = require('../env')
 
-const { outputPath: contentBase, publicPath } = require('../config')
-
 let devConfig = {
   mode: 'development',
   devtool: 'cheap-module-source-map'
 }
 
 if (runningWebpackDevServer) {
-  const liveReload = devServer.live_reload !== undefined ? devServer.live_reload : !devServer.hmr
-
-  const devServerConfig = {
-    devMiddleware: {
-      publicPath
-    },
-    compress: devServer.compress,
-    allowedHosts: devServer.allowed_hosts,
-    host: devServer.host,
-    port: devServer.port,
-    https: devServer.https,
-    hot: devServer.hmr,
-    liveReload,
-    historyApiFallback: { disableDotRule: true },
-    headers: devServer.headers,
-    static: {
-      publicPath: contentBase
-    }
-  }
-
-  if (devServer.static) {
-    devServerConfig.static = { ...devServerConfig.static, ...devServer.static }
-  }
-
-  if (devServer.client) {
-    devServerConfig.client = devServer.client
-  }
-
   devConfig = merge(devConfig, {
     stats: {
       colors: true,
diff --git a/package/environments/production.js b/package/environments/production.js
index e5e3a1286..3eff2d76d 100644
--- a/package/environments/production.js
+++ b/package/environments/production.js
@@ -52,7 +52,7 @@ const productionConfig = {
     minimizer: [
       tryCssMinimizer(),
       new TerserPlugin({
-        parallel: Number.parseInt(process.env.WEBPACKER_PARALLEL, 10) || true,
+        parallel: Number.parseInt(process.env.SHAKAPACKER_PARALLEL, 10) || true,
         terserOptions: {
           parse: {
             // Let terser parse ecma 8 code but always output
diff --git a/package/inliningCss.js b/package/inliningCss.js
index 9ca041981..73d85c636 100644
--- a/package/inliningCss.js
+++ b/package/inliningCss.js
@@ -1,7 +1,7 @@
 const { runningWebpackDevServer } = require('./env')
 const devServer = require('./dev_server')
 
-// This logic is tied to lib/webpacker/instance.rb
+// This logic is tied to lib/shakapacker/instance.rb
 const inliningCss = runningWebpackDevServer && devServer.hmr && devServer.inline_css !== false
 
 module.exports = inliningCss
diff --git a/package/rules/__tests__/file.js b/package/rules/__tests__/file.js
index 199528ee7..88a8f245a 100644
--- a/package/rules/__tests__/file.js
+++ b/package/rules/__tests__/file.js
@@ -32,4 +32,31 @@ describe('file', () => {
     ]
     types.forEach(type => expect(file.exclude.test(type)).toBe(true))
   })
+
+  test('correct generated output path is returned for top level files', () => {
+    const pathData = {
+      filename: 'app/javascript/image.svg',
+    };
+    expect(file.generator.filename(pathData)).toEqual(
+      'static/[name]-[hash][ext][query]'
+    );
+  });
+
+  test('correct generated output path is returned for nested files', () => {
+    const pathData = {
+      filename: 'app/javascript/images/image.svg',
+    };
+    expect(file.generator.filename(pathData)).toEqual(
+      'static/images/[name]-[hash][ext][query]'
+    );
+  })
+
+  test('correct generated output path is returned for deeply nested files', () => {
+    const pathData = {
+      filename: 'app/javascript/images/nested/deeply/image.svg',
+    };
+    expect(file.generator.filename(pathData)).toEqual(
+      'static/images/nested/deeply/[name]-[hash][ext][query]'
+    );
+  });
 })
diff --git a/package/rules/__tests__/swc.js b/package/rules/__tests__/swc.js
index d90d24193..c9448bae6 100644
--- a/package/rules/__tests__/swc.js
+++ b/package/rules/__tests__/swc.js
@@ -1,4 +1,3 @@
-const path = require("path");
 const {
   app_javascript,
   node_modules,
@@ -36,7 +35,7 @@ const createWebpackConfig = (file, use) => {
 };
 
 describe("swc", () => {
-  test("process source path", async () => {
+  test("process files in source_path", async () => {
     const normalPath = `${app_javascript}/a.js`;
     const [tracked, loader] = createTrackLoader();
     const compiler = createTestCompiler(
diff --git a/package/rules/file.js b/package/rules/file.js
index 9a6bf196e..6c5fdde01 100644
--- a/package/rules/file.js
+++ b/package/rules/file.js
@@ -8,9 +8,9 @@ module.exports = {
   generator: {
     filename: (pathData) => {
       const folders = dirname(pathData.filename)
-        .replace(`${sourcePath}/`, '')
+        .replace(`${sourcePath}`, '')
         .split('/')
-        .slice(1)
+        .filter(Boolean)
 
       const foldersWithStatic = ['static', ...folders].join('/')
       return `${foldersWithStatic}/[name]-[hash][ext][query]`
diff --git a/package/utils/helpers.js b/package/utils/helpers.js
index e59c65404..397f1113a 100644
--- a/package/utils/helpers.js
+++ b/package/utils/helpers.js
@@ -8,6 +8,15 @@ const chdirTestApp = () => {
   }
 }
 
+// For backward compatibility
+const chdirWebpackerTestApp = () => {
+  try {
+    return process.chdir('spec/backward_compatibility_specs/webpacker_test_app')
+  } catch (e) {
+    return null
+  }
+}
+
 const chdirCwd = () => process.chdir(process.cwd())
 
 const resetEnv = () => {
@@ -48,15 +57,29 @@ const loaderMatches = (configLoader, loaderToCheck, fn) => {
 
   if (!moduleExists(loaderName)) {
     throw new Error(
-      `Your webpacker config specified using ${configLoader}, but ${loaderName} package is not installed. Please install ${loaderName} first.`
+      `Your Shakapacker config specified using ${configLoader}, but ${loaderName} package is not installed. Please install ${loaderName} first.`
     )
   }
 
   return fn()
 }
 
+// For backward compatibility
+// Set SHAKAPACKER_XYZ only if SHAKAPACKER_XYZ is not defined but WEBPACKER_XYZ is.
+const setShakapackerEnvVariablesForBackwardCompatibility = () => {
+  const webpackerEnvVariables = Object.entries(process.env).filter((key) => /^WEBPACKER_/.test(key))
+  webpackerEnvVariables.forEach(([webpackerEnvKey, webpackerEnvValue]) => {
+    const shakapackerKey = webpackerEnvKey.replace(/^WEBPACKER/, 'SHAKAPACKER')
+    if (!process.env[shakapackerKey]) {
+      process.env[shakapackerKey] = webpackerEnvValue
+    }
+  })
+}
+
 module.exports = {
   chdirTestApp,
+  chdirWebpackerTestApp,
+  setShakapackerEnvVariablesForBackwardCompatibility,
   chdirCwd,
   isArray,
   isBoolean,
diff --git a/webpacker.gemspec b/shakapacker.gemspec
similarity index 89%
rename from webpacker.gemspec
rename to shakapacker.gemspec
index 4392e97e0..b095a7b0d 100644
--- a/webpacker.gemspec
+++ b/shakapacker.gemspec
@@ -1,16 +1,16 @@
 $:.push File.expand_path("../lib", __FILE__)
-require "webpacker/version"
+require "shakapacker/version"
 
 Gem::Specification.new do |s|
   s.name     = "shakapacker"
-  s.version  = Webpacker::VERSION
+  s.version  = Shakapacker::VERSION
   s.authors  = [ "David Heinemeier Hansson", "Gaurav Tiwari", "Justin Gordon" ]
   s.email    = [ "david@basecamp.com", "gaurav@gauravtiwari.co.uk", "justin@shakacode.com" ]
   s.summary  = "Use webpack to manage app-like JavaScript modules in Rails"
   s.homepage = "https://github.com/shakacode/shakapacker"
   s.license  = "MIT"
 
-  npm_version = Webpacker::VERSION.gsub(".rc", "-rc")
+  npm_version = Shakapacker::VERSION.gsub(".rc", "-rc")
   s.metadata = {
     "source_code_uri" => "https://github.com/shakacode/shakapacker/tree/v#{npm_version}",
   }
diff --git a/spec/backward_compatibility_specs/command_spec_bc.rb b/spec/backward_compatibility_specs/command_spec_bc.rb
new file mode 100644
index 000000000..cae9d4f8b
--- /dev/null
+++ b/spec/backward_compatibility_specs/command_spec_bc.rb
@@ -0,0 +1,116 @@
+require_relative "spec_helper_initializer"
+
+describe "Command" do
+  before do
+    allow(Webpacker.logger).to receive(:info)
+  end
+
+  describe "#compile" do
+    it "returns success status when stale" do
+      expect(Webpacker.compiler).to receive(:stale?).and_return(true)
+      expect(Webpacker.compiler).to receive(:run_webpack).and_return(true)
+
+      expect(Webpacker.commands.compile).to be true
+    end
+
+    it "returns success status when fresh" do
+      expect(Webpacker.compiler).to receive(:stale?).and_return(false)
+
+      expect(Webpacker.commands.compile).to be true
+    end
+
+    it "returns failure status when stale" do
+      expect(Webpacker.compiler).to receive(:stale?).and_return(true)
+      expect(Webpacker.compiler).to receive(:run_webpack).and_return(false)
+
+      expect(Webpacker.commands.compile).to be false
+    end
+  end
+
+  describe "#clean" do
+    let(:now) { Time.parse("2021-01-01 12:34:56 UTC") }
+    let(:prev_files) do
+      # Test assets to be kept and deleted, path and mtime
+      {
+        # recent versions to be kept with Webpacker.commands.clean(count = 2)
+        "js/application-deadbeef.js" => now - 4000,
+        "js/common-deadbeee.js" => now - 4002,
+        "css/common-deadbeed.css" => now - 4004,
+        "media/images/logo-deadbeeb.css" => now - 4006,
+        "js/application-1eadbeef.js" => now - 8000,
+        "js/common-1eadbeee.js" => now - 8002,
+        "css/common-1eadbeed.css" => now - 8004,
+        "media/images/logo-1eadbeeb.css" => now - 8006,
+        # new files to be kept with Webpacker.commands.clean(age = 3600)
+        "js/brandnew-0001.js" => now,
+        "js/brandnew-0002.js" => now - 10,
+        "js/brandnew-0003.js" => now - 20,
+        "js/brandnew-0004.js" => now - 40,
+      }.transform_keys { |path| "#{Webpacker.config.public_output_path}/#{path}" }
+    end
+
+    let(:expired_files) do
+      {
+        # old files that are outside count = 2 or age = 3600 and to be deleted
+        "js/application-0eadbeef.js" => now - 9000,
+        "js/common-0eadbeee.js" => now - 9002,
+        "css/common-0eadbeed.css" => now - 9004,
+        "js/brandnew-0005.js" => now - 3640,
+      }.transform_keys { |path| "#{Webpacker.config.public_output_path}/#{path}" }
+    end
+
+    let(:all_files) { prev_files.merge(expired_files) }
+
+    let(:file_delete_mock) { double("File Delete") }
+    let(:file_mtime_stub) { Proc.new { |longpath| all_files[longpath] } }
+    let(:file_delete_stub) { Proc.new { |longpath| file_delete_mock.delete(longpath) } }
+
+    before :context do
+      @dir_glob_stub = Proc.new { |arg|
+        case arg
+        when "#{Webpacker.config.public_output_path}/**/*"
+          all_files.keys
+        else
+          []
+        end
+      }
+    end
+
+    it "works with nested hashes and without any compiled files" do
+      allow(File).to receive(:delete).and_return(true)
+      expect(Webpacker.commands.clean).to be true
+    end
+
+    it "deletes only and only expired versioned files if no parameter passed" do
+      all_files.keys.each do |longpath|
+        allow(file_delete_mock).to receive(:delete).with(longpath)
+      end
+
+      with_time_dir_and_files_stub do
+        expect(Webpacker.commands.clean).to be true
+
+        # Verify that only and only expired files are deleted
+        all_files.keys.each do |longpath|
+          if expired_files.has_key? longpath
+            expect(file_delete_mock).to have_received(:delete).with(longpath)
+          else
+            expect(file_delete_mock).to_not have_received(:delete).with(longpath)
+          end
+        end
+      end
+    end
+
+    private
+
+      def with_time_dir_and_files_stub(&proc)
+        allow(Time).to receive(:now).and_return(now)
+        allow(Dir).to receive(:glob) { |arg| @dir_glob_stub.call(arg) }
+        allow(File).to receive(:directory?).and_return(false)
+        allow(File).to receive(:file?).and_return(true)
+        allow(File).to receive(:mtime) { |arg| file_mtime_stub.call(arg) }
+        allow(File).to receive(:delete) { |arg| file_delete_stub.call(arg) }
+
+        yield proc
+      end
+  end
+end
diff --git a/spec/backward_compatibility_specs/compiler_spec_bc.rb b/spec/backward_compatibility_specs/compiler_spec_bc.rb
new file mode 100644
index 000000000..bfdb931aa
--- /dev/null
+++ b/spec/backward_compatibility_specs/compiler_spec_bc.rb
@@ -0,0 +1,59 @@
+require_relative "spec_helper_initializer"
+
+describe "Webpacker::Compiler" do
+  it "accepts custom environment variables" do
+    expect(Webpacker.compiler.send(:webpack_env)["FOO"]).to be nil
+
+    Webpacker.compiler.env["FOO"] = "BAR"
+    expect(Webpacker.compiler.send(:webpack_env)["FOO"]).to eq "BAR"
+  ensure
+    Webpacker.compiler.env = {}
+  end
+
+  it "returns true when fresh" do
+    mocked_strategy = double("Strategy")
+    expect(mocked_strategy).to receive(:stale?).and_return(false)
+
+    expect(Webpacker.compiler).to receive(:strategy).and_return(mocked_strategy)
+
+    expect(Webpacker.compiler.compile).to be true
+  end
+
+  it "returns true and calls after_compile_hook on successful compile" do
+    mocked_strategy = spy("Strategy")
+    expect(mocked_strategy).to receive(:stale?).and_return(true)
+
+    allow(Webpacker.compiler).to receive(:strategy).and_return(mocked_strategy)
+
+    status = OpenStruct.new(success?: true)
+    allow(Open3).to receive(:capture3).and_return([:sterr, :stdout, status])
+
+    expect(Webpacker.compiler.compile).to be true
+    expect(mocked_strategy).to have_received(:after_compile_hook)
+  end
+
+  it "returns false and calls after_compile_hook on failed compile" do
+    mocked_strategy = spy("Strategy")
+    allow(mocked_strategy).to receive(:stale?).and_return(true)
+    allow(mocked_strategy).to receive(:after_compile_hook)
+
+    allow(Webpacker.compiler).to receive(:strategy).and_return(mocked_strategy)
+
+    status = OpenStruct.new(success?: false)
+    allow(Open3).to receive(:capture3).and_return([:sterr, :stdout, status])
+
+    expect(Webpacker.compiler.compile).to be false
+    expect(mocked_strategy).to have_received(:after_compile_hook)
+  end
+
+  it "accepts external env variables" do
+    expect(Webpacker.compiler.send(:webpack_env)["SHAKAPACKER_ASSET_HOST"]).to be nil
+    expect(Webpacker.compiler.send(:webpack_env)["SHAKAPACKER_RELATIVE_URL_ROOT"]).to be nil
+
+    ENV["WEBPACKER_ASSET_HOST"] = "foo.bar"
+    ENV["WEBPACKER_RELATIVE_URL_ROOT"] = "/baz"
+
+    expect(Webpacker.compiler.send(:webpack_env)["SHAKAPACKER_ASSET_HOST"]).to eq "foo.bar"
+    expect(Webpacker.compiler.send(:webpack_env)["SHAKAPACKER_RELATIVE_URL_ROOT"]).to eq "/baz"
+  end
+end
diff --git a/spec/backward_compatibility_specs/compiler_strategy_spec_bc.rb b/spec/backward_compatibility_specs/compiler_strategy_spec_bc.rb
new file mode 100644
index 000000000..838eb4692
--- /dev/null
+++ b/spec/backward_compatibility_specs/compiler_strategy_spec_bc.rb
@@ -0,0 +1,22 @@
+require_relative "spec_helper_initializer"
+
+describe "Webpacker::CompilerStrategy" do
+  describe "#from_config" do
+    it "returns and instance of MtimeStrategy when compiler_strategy is set to mtime" do
+      allow(Webpacker.config).to receive(:compiler_strategy).and_return("mtime")
+      expect(Webpacker::CompilerStrategy.from_config).to be_an_instance_of(Webpacker::MtimeStrategy)
+    end
+
+    it "returns and instance of DigestStrategy when compiler_strategy is set to digest" do
+      allow(Webpacker.config).to receive(:compiler_strategy).and_return("digest")
+      expect(Webpacker::CompilerStrategy.from_config).to be_an_instance_of(Webpacker::DigestStrategy)
+    end
+
+    it "raise exception for unknown compiler_strategy in the config file" do
+      expected_error_message = "Unknown strategy 'other'. Available options are 'mtime' and 'digest'."
+      allow(Webpacker.config).to receive(:compiler_strategy).and_return("other")
+
+      expect { Webpacker::CompilerStrategy.from_config }.to raise_error(expected_error_message)
+    end
+  end
+end
diff --git a/spec/backward_compatibility_specs/configuration_spec_bc.rb b/spec/backward_compatibility_specs/configuration_spec_bc.rb
new file mode 100644
index 000000000..ebfacff66
--- /dev/null
+++ b/spec/backward_compatibility_specs/configuration_spec_bc.rb
@@ -0,0 +1,286 @@
+require_relative "spec_helper_initializer"
+
+describe "Webpacker::Configuration" do
+  ROOT_PATH = Pathname.new(File.expand_path("webpacker_test_app", __dir__))
+
+  context "with standard webpacker.yml" do
+    let(:config) do
+      Webpacker::Configuration.new(
+        root_path: ROOT_PATH,
+        config_path: Pathname.new(File.expand_path("./webpacker_test_app/config/webpacker.yml", __dir__)),
+        env: "production"
+      )
+    end
+
+    it "#source_path returns correct path" do
+      source_path = File.expand_path File.join(File.dirname(__FILE__), "webpacker_test_app/app/packs").to_s
+      expect(config.source_path.to_s).to eq source_path
+    end
+
+    it "#source_entry_path returns correct path" do
+      source_entry_path = File.expand_path File.join(File.dirname(__FILE__), "webpacker_test_app/app/packs", "entrypoints").to_s
+      expect(config.source_entry_path.to_s).to eq source_entry_path
+    end
+
+    it "#public_root_path returns correct path" do
+      public_root_path = File.expand_path File.join(File.dirname(__FILE__), "webpacker_test_app/public").to_s
+      expect(config.public_path.to_s).to eq public_root_path
+    end
+
+    it "#public_output_path returns correct path" do
+      public_output_path = File.expand_path File.join(File.dirname(__FILE__), "webpacker_test_app/public/packs").to_s
+      expect(config.public_output_path.to_s).to eq public_output_path
+    end
+
+    it "#public_manifest_path returns correct path" do
+      public_manifest_path = File.expand_path File.join(File.dirname(__FILE__), "webpacker_test_app/public/packs", "manifest.json").to_s
+      expect(config.public_manifest_path.to_s).to eq public_manifest_path
+    end
+
+    it "#manifest_path returns correct path" do
+      manifest_path = File.expand_path File.join(File.dirname(__FILE__), "webpacker_test_app/public/packs", "manifest.json").to_s
+      expect(config.manifest_path.to_s).to eq manifest_path
+    end
+
+    it "#cache_path returns correct path" do
+      cache_path = File.expand_path File.join(File.dirname(__FILE__), "webpacker_test_app/tmp/webpacker").to_s
+      expect(config.cache_path.to_s).to eq cache_path
+    end
+
+    it "#additional_paths returns correct path" do
+      expect(config.additional_paths).to eq ["app/assets", "/etc/yarn", "some.config.js", "app/elm"]
+    end
+
+    describe "#cache_manifest?" do
+      it "returns true in production environment" do
+        expect(config.cache_manifest?).to be true
+      end
+
+      it "returns false in developemnt environemnt" do
+        with_rails_env("development") do
+          expect(Webpacker.config.cache_manifest?).to be false
+        end
+      end
+
+      it "returns false in test environment" do
+        with_rails_env("test") do
+          expect(Webpacker.config.cache_manifest?).to be false
+        end
+      end
+    end
+
+    describe "#compile?" do
+      it "returns false in production environment" do
+        expect(config.compile?).to be false
+      end
+
+      it "returns true in developemnt environemnt" do
+        with_rails_env("development") do
+          expect(Webpacker.config.compile?).to be true
+        end
+      end
+
+      it "returns true in test environemnt" do
+        with_rails_env("test") do
+          expect(Webpacker.config.compile?).to be true
+        end
+      end
+    end
+
+    describe "#nested_entries?" do
+      it "returns false in production environment" do
+        expect(config.nested_entries?).to be false
+      end
+
+      it "returns false in development environment" do
+        with_rails_env("development") do
+          expect(Webpacker.config.nested_entries?).to be false
+        end
+      end
+
+      it "returns false in test environment" do
+        with_rails_env("test") do
+          expect(Webpacker.config.nested_entries?).to be false
+        end
+      end
+    end
+
+    describe "#ensure_consistent_versioning?" do
+      it "returns false in production environment" do
+        expect(config.ensure_consistent_versioning?).to be false
+      end
+
+      it "returns true in development environment" do
+        with_rails_env("development") do
+          expect(Webpacker.config.ensure_consistent_versioning?).to be true
+        end
+      end
+
+      it "returns false in test environment" do
+        with_rails_env("test") do
+          expect(Webpacker.config.ensure_consistent_versioning?).to be false
+        end
+      end
+    end
+
+    describe "#webpacker_precompile?" do
+      before :each do
+        ENV.delete("SHAKAPACKER_PRECOMPILE")
+        ENV.delete("WEBPACKER_PRECOMPILE")
+      end
+
+      subject { config.webpacker_precompile? }
+
+      it "returns true when WEBPACKER_PRECOMPILE is unset" do
+        is_expected.to be true
+      end
+
+      it "returns false when WEBPACKER_PRECOMPILE sets to no" do
+        ENV["WEBPACKER_PRECOMPILE"] = "no"
+        is_expected.to be false
+      end
+
+      it "returns true when WEBPACKER_PRECOMPILE sets to yes" do
+        ENV["WEBPACKER_PRECOMPILE"] = "yes"
+        is_expected.to be true
+      end
+
+      it "returns false when WEBPACKER_PRECOMPILE sets to false" do
+        ENV["WEBPACKER_PRECOMPILE"] = "false"
+        is_expected.to be false
+      end
+
+      it "returns true when WEBPACKER_PRECOMPILE sets to true" do
+        ENV["WEBPACKER_PRECOMPILE"] = "true"
+        is_expected.to be true
+      end
+
+      it "returns false when WEBPACKER_PRECOMPILE sets to n" do
+        ENV["WEBPACKER_PRECOMPILE"] = "n"
+        is_expected.to be false
+      end
+
+      it "returns true when WEBPACKER_PRECOMPILE sets to y" do
+        ENV["WEBPACKER_PRECOMPILE"] = "y"
+        is_expected.to be true
+      end
+
+      it "returns false when WEBPACKER_PRECOMPILE sets to f" do
+        ENV["WEBPACKER_PRECOMPILE"] = "f"
+        is_expected.to be false
+      end
+
+      it "returns true when WEBPACKER_PRECOMPILE sets to t" do
+        ENV["WEBPACKER_PRECOMPILE"] = "t"
+        is_expected.to be true
+      end
+    end
+  end
+
+  context "with webpacker config file containing public_output_path entry" do
+    config = Webpacker::Configuration.new(
+      root_path: ROOT_PATH,
+      config_path: Pathname.new(File.expand_path("./webpacker_test_app/config/webpacker_public_root.yml", __dir__)),
+      env: "production"
+    )
+
+    it "#public_output_path returns correct path" do
+      expected_public_output_path = File.expand_path File.join(File.dirname(__FILE__), "public/packs").to_s
+      expect(config.public_output_path.to_s).to eq expected_public_output_path
+    end
+  end
+
+  context "with webpacker config file containing manifext_path entry" do
+    config = Webpacker::Configuration.new(
+      root_path: ROOT_PATH,
+      config_path: Pathname.new(File.expand_path("./webpacker_test_app/config/webpacker_manifest_path.yml", __dir__)),
+      env: "production"
+    )
+
+    it "#manifest_path returns correct expected value" do
+      expected_manifest_path = File.expand_path File.join(File.dirname(__FILE__), "webpacker_test_app/app/packs", "manifest.json").to_s
+      expect(config.manifest_path.to_s).to eq expected_manifest_path
+    end
+  end
+
+  context "with webpacker_precompile entry set to false" do
+    describe "#webpacker_precompile?" do
+      before :each do
+        ENV.delete("WEBPACKER_PRECOMPILE")
+        ENV.delete("SHAKAPACKER_PRECOMPILE")
+      end
+
+      let(:config) {
+        Webpacker::Configuration.new(
+          root_path: ROOT_PATH,
+          config_path: Pathname.new(File.expand_path("./webpacker_test_app/config/webpacker_no_precompile.yml", __dir__)),
+          env: "production"
+        )
+      }
+
+      subject { config.webpacker_precompile? }
+
+      it "returns false with unset WEBPACKER_PRECOMPILE" do
+        expect(subject).to be false
+      end
+
+      it "returns true with WEBPACKER_PRECOMPILE set to true" do
+        ENV["WEBPACKER_PRECOMPILE"] = "true"
+        expect(subject).to be true
+      end
+
+      it "returns false with WEBPACKER_PRECOMPILE set to falsy value" do
+        # ENV["WEBPACKER_PRECOMPILE"] = "no"
+        ENV.delete("WEBPACKER_PRECOMPILE")
+        expect(subject).to be false
+      end
+    end
+  end
+
+  context "with webpacker config file containing invalid path" do
+    config = Webpacker::Configuration.new(
+      root_path: ROOT_PATH,
+      config_path: Pathname.new(File.expand_path("./webpacker_test_app/config/invalid_path.yml", __dir__)),
+      env: "default"
+    )
+
+    it "#webpacker_precompile? returns false" do
+      expect(config.webpacker_precompile?).to be false
+    end
+  end
+
+  context "with webpacker config file with defaults fallback" do
+    let(:config) do
+      Webpacker::Configuration.new(
+        root_path: ROOT_PATH,
+        config_path: Pathname.new(File.expand_path("./webpacker_test_app/config/webpacker_defaults_fallback.yml", __dir__)),
+        env: "default"
+      )
+    end
+
+    it "#cache_manifest? falls back to 'default' config from bundled file" do
+      expect(config.cache_manifest?).to be false
+    end
+
+    it "#webpacker_precompile? uses 'default' config from custom file" do
+      expect(config.webpacker_precompile?).to be false
+    end
+  end
+
+  context "falls back to bundled production config for custom environments" do
+    let(:config) do
+      Webpacker::Configuration.new(
+        root_path: ROOT_PATH,
+        config_path: Pathname.new(File.expand_path("./webpacker_test_app/config/webpacker_defaults_fallback.yml", __dir__)),
+        env: "staging"
+      )
+    end
+
+    it "#cache_manifest? fall back to 'production' config from bundled file" do
+      expect(config.cache_manifest?).to be true
+    end
+    it "#webpacker_precompile? use 'staging' config from custom file" do
+      expect(config.webpacker_precompile?).to be false
+    end
+  end
+end
diff --git a/spec/backward_compatibility_specs/dev_server_runner_spec_bc.rb b/spec/backward_compatibility_specs/dev_server_runner_spec_bc.rb
new file mode 100644
index 000000000..c25a10b84
--- /dev/null
+++ b/spec/backward_compatibility_specs/dev_server_runner_spec_bc.rb
@@ -0,0 +1,79 @@
+require_relative "spec_helper_initializer"
+# Requiring from webpacker directory to ensure old ./bin/webpacker-dev-server works fine
+require "webpacker/dev_server_runner"
+
+describe "DevServerRunner" do
+  before do
+    @original_node_env, ENV["NODE_ENV"] = ENV["NODE_ENV"], "development"
+    @original_rails_env, ENV["RAILS_ENV"] = ENV["RAILS_ENV"], "development"
+    @original_webpacker_config = ENV["WEBPACKER_CONFIG"]
+  end
+
+  after do
+    ENV["NODE_ENV"] = @original_node_env
+    ENV["RAILS_ENV"] = @original_rails_env
+    ENV["WEBPACKER_CONFIG"] = @original_webpacker_config
+  end
+
+  let(:test_app_path) { File.expand_path("webpacker_test_app", __dir__) }
+
+  it "run cmd via node modules" do
+    cmd = ["#{test_app_path}/node_modules/.bin/webpack", "serve", "--config", "#{test_app_path}/config/webpack/webpack.config.js"]
+    verify_command(cmd, use_node_modules: true)
+  end
+
+  it "run cmd via yarn" do
+    cmd = ["yarn", "webpack", "serve", "--config", "#{test_app_path}/config/webpack/webpack.config.js"]
+    verify_command(cmd, use_node_modules: false)
+  end
+
+  it "run cmd argv" do
+    cmd = ["#{test_app_path}/node_modules/.bin/webpack", "serve", "--config", "#{test_app_path}/config/webpack/webpack.config.js", "--quiet"]
+    verify_command(cmd, argv: (["--quiet"]))
+  end
+
+  it "run cmd argv with https" do
+    cmd = ["#{test_app_path}/node_modules/.bin/webpack", "serve", "--config", "#{test_app_path}/config/webpack/webpack.config.js", "--https"]
+
+    dev_server = double()
+    allow(dev_server).to receive(:host).and_return("localhost")
+    allow(dev_server).to receive(:port).and_return("3035")
+    allow(dev_server).to receive(:pretty?).and_return(false)
+    allow(dev_server).to receive(:https?).and_return(true)
+    allow(dev_server).to receive(:hmr?).and_return(false)
+
+    allow(Webpacker::DevServer).to receive(:new) do
+      verify_command(cmd, argv: (["--https"]))
+    end.and_return(dev_server)
+  end
+
+  it "accepts environment variables" do
+    cmd = ["#{test_app_path}/node_modules/.bin/webpack", "serve", "--config", "#{test_app_path}/config/webpack/webpack.config.js"]
+    env = Webpacker::Compiler.env.dup
+
+    # ENV["WEBPACKER_CONFIG"] is the interface and env["SHAKAPACKER_CONFIG"] is internal
+    ENV["WEBPACKER_CONFIG"] = env["SHAKAPACKER_CONFIG"] = "#{test_app_path}/config/webpacker_other_location.yml"
+    env["WEBPACK_SERVE"] = "true"
+    verify_command(cmd, env: env)
+  end
+
+  private
+
+    def verify_command(cmd, use_node_modules: true, argv: [], env: Webpacker::Compiler.env)
+      cwd = Dir.pwd
+      Dir.chdir(test_app_path)
+      klass = Webpacker::DevServerRunner
+      instance = klass.new(argv)
+
+      allow(klass).to receive(:new).and_return(instance)
+      allow(instance).to receive(:node_modules_bin_exist?).and_return(use_node_modules)
+      allow(Kernel).to receive(:exec).with(env, *cmd)
+
+      klass.run(argv)
+
+      expect(Kernel).to have_received(:exec).with(env, *cmd)
+
+      ensure
+        Dir.chdir(cwd)
+    end
+end
diff --git a/spec/backward_compatibility_specs/dev_server_spec_bc.rb b/spec/backward_compatibility_specs/dev_server_spec_bc.rb
new file mode 100644
index 000000000..bc084bf13
--- /dev/null
+++ b/spec/backward_compatibility_specs/dev_server_spec_bc.rb
@@ -0,0 +1,47 @@
+require_relative "spec_helper_initializer"
+
+describe "DevServer" do
+  it "doesn't run by default" do
+    expect(Webpacker.dev_server.running?).to be_falsy
+  end
+
+  it "uses localhost as host in development environment" do
+    with_rails_env("development") do
+      expect(Webpacker.dev_server.host).to eq "localhost"
+    end
+  end
+
+  it "uses port 3035 in development environment" do
+    with_rails_env("development") do
+      expect(Webpacker.dev_server.port).to eq 3035
+    end
+  end
+
+  it "doesn't use https in development environment" do
+    with_rails_env("development") do
+      expect(Webpacker.dev_server.https?).to be false
+    end
+  end
+
+  it "uses http protocol in development environment" do
+    with_rails_env("development") do
+      expect(Webpacker.dev_server.protocol).to eq "http"
+    end
+  end
+
+  it "sets host_with_port to localhost:3035 in development environment" do
+    with_rails_env("development") do
+      expect(Webpacker.dev_server.host_with_port).to eq "localhost:3035"
+    end
+  end
+
+  it "doesn't use pretty in development environment" do
+    with_rails_env("development") do
+      expect(Webpacker.dev_server.pretty?).to be false
+    end
+  end
+
+  it "users SHAKAPACKER_DEV_SERVER for DEFAULT_ENV_PREFIX" do
+    expect(Webpacker::DevServer::DEFAULT_ENV_PREFIX).to eq "SHAKAPACKER_DEV_SERVER"
+  end
+end
diff --git a/spec/backward_compatibility_specs/digest_strategy_spec_bc.rb b/spec/backward_compatibility_specs/digest_strategy_spec_bc.rb
new file mode 100644
index 000000000..86f17e696
--- /dev/null
+++ b/spec/backward_compatibility_specs/digest_strategy_spec_bc.rb
@@ -0,0 +1,35 @@
+require_relative "spec_helper_initializer"
+
+describe "DigestStrategy" do
+  def remove_compilation_digest_path
+    @digest_strategy.send(:compilation_digest_path).tap do |path|
+      path.delete if path.exist?
+    end
+  end
+
+  before :all do
+    @digest_strategy = Webpacker::DigestStrategy.new
+    remove_compilation_digest_path
+  end
+
+  after :all do
+    remove_compilation_digest_path
+  end
+
+  it "is not fresh before compilation" do
+    expect(@digest_strategy.stale?).to be true
+    expect(@digest_strategy.fresh?).to be_falsy
+  end
+
+  it "is fresh after compilation" do
+    @digest_strategy.after_compile_hook
+    expect(@digest_strategy.stale?).to be false
+    expect(@digest_strategy.fresh?).to be true
+  end
+
+  it "generates correct compilation_digest_path" do
+    actual_path = @digest_strategy.send(:compilation_digest_path).basename.to_s
+    expected_path = "last-compilation-digest-#{Webpacker.env}"
+    expect(actual_path).to eq expected_path
+  end
+end
diff --git a/spec/backward_compatibility_specs/engine_rake_tasks_spec_bc.rb b/spec/backward_compatibility_specs/engine_rake_tasks_spec_bc.rb
new file mode 100644
index 000000000..fa6fe812d
--- /dev/null
+++ b/spec/backward_compatibility_specs/engine_rake_tasks_spec_bc.rb
@@ -0,0 +1,44 @@
+require_relative "spec_helper_initializer"
+
+describe "EngineRakeTasks" do
+  before :context do
+    remove_webpack_binstubs
+  end
+
+  after :context do
+    remove_webpack_binstubs
+  end
+
+  it "mounts app:webpacker task successfully" do
+    output = Dir.chdir(mounted_app_path) { `rake -T` }
+    expect(output).to match /app:webpacker.+DEPRECATED/
+    expect(output).to match /app:webpacker:binstubs.+DEPRECATED/
+  end
+
+  it "binstubs adds only expected files to bin directory" do
+    Dir.chdir(mounted_app_path) { `bundle exec rake app:webpacker:binstubs` }
+    expected_binstub_paths.each { |path| expect(File.exist?(path)).to be true }
+  end
+
+  private
+    def mounted_app_path
+      File.expand_path("../mounted_app", __dir__)
+    end
+
+    def current_files_in_bin
+      Dir.glob("#{mounted_app_path}/test/dummy/bin/*")
+    end
+
+    def expected_binstub_paths
+      gem_path = File.expand_path("../..", __dir__)
+      Dir.chdir("#{gem_path}/lib/install/bin") do
+        Dir.glob("*").map { |file| "#{mounted_app_path}/test/dummy/bin/#{file}" }
+      end
+    end
+
+    def remove_webpack_binstubs
+      expected_binstub_paths.each do |path|
+        File.delete(path) if File.exist?(path)
+      end
+    end
+end
diff --git a/spec/backward_compatibility_specs/env_spec_bc.rb b/spec/backward_compatibility_specs/env_spec_bc.rb
new file mode 100644
index 000000000..82d02959f
--- /dev/null
+++ b/spec/backward_compatibility_specs/env_spec_bc.rb
@@ -0,0 +1,23 @@
+require_relative "spec_helper_initializer"
+
+RSpec.describe "Webpacker.env" do
+  it "uses the same env for Rails and Webpacker" do
+    expect(Webpacker.env).to eq Rails.env
+  end
+
+  it "uses production env without config" do
+    with_rails_env("foo") do
+      expect(Webpacker.env).to eq "production"
+    end
+  end
+
+  it "uses the given env in custom config" do
+    with_rails_env("staging") do
+      expect(Webpacker.env).to eq "staging"
+    end
+  end
+
+  it "uses 'production' as default env" do
+    expect(Webpacker::DEFAULT_ENV).to eq "production"
+  end
+end
diff --git a/spec/backward_compatibility_specs/helper_spec_bc.rb b/spec/backward_compatibility_specs/helper_spec_bc.rb
new file mode 100644
index 000000000..ca6a2995f
--- /dev/null
+++ b/spec/backward_compatibility_specs/helper_spec_bc.rb
@@ -0,0 +1,243 @@
+require_relative "spec_helper_initializer"
+
+module ActionView::TestCase::Behavior
+  attr_accessor :request
+
+  describe "Webpacker::Helper" do
+    let(:application_stylesheet_chunks) { %w[/packs/1-c20632e7baf2c81200d3.chunk.css /packs/application-k344a6d59eef8632c9d1.chunk.css] }
+    let(:hello_stimulus_stylesheet_chunks) { %w[/packs/1-c20632e7baf2c81200d3.chunk.css /packs/hello_stimulus-k344a6d59eef8632c9d1.chunk.css] }
+
+    before :each do
+      extend Webpacker::Helper
+      extend ActionView::Helpers
+      extend ActionView::Helpers::AssetTagHelper
+      extend ActionView::TestCase::Behavior
+
+      @request = Class.new do
+        def send_early_hints(links) end
+        def base_url
+          "https://example.com"
+        end
+      end.new
+      @javascript_pack_tag_loaded = nil
+    end
+
+    it "#asset_pack_path generates correct path" do
+      expect(asset_pack_path("bootstrap.js")).to eq "/packs/bootstrap-300631c4f0e0f9c865bc.js"
+      expect(asset_pack_path("bootstrap.css")).to eq "/packs/bootstrap-c38deda30895059837cf.css"
+    end
+
+    it "#asset_pack_url generates correct url" do
+      expect(asset_pack_url("bootstrap.js")).to eq "https://example.com/packs/bootstrap-300631c4f0e0f9c865bc.js"
+      expect(asset_pack_url("bootstrap.css")).to eq "https://example.com/packs/bootstrap-c38deda30895059837cf.css"
+    end
+
+    it "#image_pack_path generates correct path" do
+      expect(image_pack_path("application.png")).to eq "/packs/application-k344a6d59eef8632c9d1.png"
+      expect(image_pack_path("image.jpg")).to eq "/packs/static/image-c38deda30895059837cf.jpg"
+      expect(image_pack_path("static/image.jpg")).to eq "/packs/static/image-c38deda30895059837cf.jpg"
+      expect(image_pack_path("nested/image.jpg")).to eq "/packs/static/nested/image-c38deda30895059837cf.jpg"
+      expect(image_pack_path("static/nested/image.jpg")).to eq "/packs/static/nested/image-c38deda30895059837cf.jpg"
+    end
+
+    it "#image_pack_url generates correct path" do
+      expect(image_pack_url("application.png")).to eq "https://example.com/packs/application-k344a6d59eef8632c9d1.png"
+      expect(image_pack_url("image.jpg")).to eq "https://example.com/packs/static/image-c38deda30895059837cf.jpg"
+      expect(image_pack_url("static/image.jpg")).to eq "https://example.com/packs/static/image-c38deda30895059837cf.jpg"
+      expect(image_pack_url("nested/image.jpg")).to eq "https://example.com/packs/static/nested/image-c38deda30895059837cf.jpg"
+      expect(image_pack_url("static/nested/image.jpg")).to eq "https://example.com/packs/static/nested/image-c38deda30895059837cf.jpg"
+    end
+
+    it "#image_pack_tag generates correct tags" do
+      expect(image_pack_tag("application.png", size: "16x10", alt: "Edit Entry")).to eq "<img alt=\"Edit Entry\" src=\"/packs/application-k344a6d59eef8632c9d1.png\" width=\"16\" height=\"10\" />"
+      expect(image_pack_tag("image.jpg", size: "16x10", alt: "Edit Entry")).to eq "<img alt=\"Edit Entry\" src=\"/packs/static/image-c38deda30895059837cf.jpg\" width=\"16\" height=\"10\" />"
+      expect(image_pack_tag("static/image.jpg", size: "16x10", alt: "Edit Entry")).to eq "<img alt=\"Edit Entry\" src=\"/packs/static/image-c38deda30895059837cf.jpg\" width=\"16\" height=\"10\" />"
+      expect(image_pack_tag("nested/image.jpg", size: "16x10", alt: "Edit Entry")).to eq "<img alt=\"Edit Entry\" src=\"/packs/static/nested/image-c38deda30895059837cf.jpg\" width=\"16\" height=\"10\" />"
+      expect(image_pack_tag("static/nested/image.jpg", size: "16x10", alt: "Edit Entry")).to eq "<img alt=\"Edit Entry\" src=\"/packs/static/nested/image-c38deda30895059837cf.jpg\" width=\"16\" height=\"10\" />"
+      expect(image_pack_tag("static/image.jpg", srcset: { "static/image-2x.jpg" => "2x" })).to eq "<img srcset=\"/packs/static/image-2x-7cca48e6cae66ec07b8e.jpg 2x\" src=\"/packs/static/image-c38deda30895059837cf.jpg\" />"
+    end
+
+    it "#favicon_pack_tag generates correct tags" do
+      expect(favicon_pack_tag("application.png", rel: "apple-touch-icon", type: "image/png")).to eq "<link rel=\"apple-touch-icon\" type=\"image/png\" href=\"/packs/application-k344a6d59eef8632c9d1.png\" />"
+      expect(favicon_pack_tag("mb-icon.png", rel: "apple-touch-icon", type: "image/png")).to eq "<link rel=\"apple-touch-icon\" type=\"image/png\" href=\"/packs/static/mb-icon-c38deda30895059837cf.png\" />"
+      expect(favicon_pack_tag("static/mb-icon.png", rel: "apple-touch-icon", type: "image/png")).to eq "<link rel=\"apple-touch-icon\" type=\"image/png\" href=\"/packs/static/mb-icon-c38deda30895059837cf.png\" />"
+      expect(favicon_pack_tag("nested/mb-icon.png", rel: "apple-touch-icon", type: "image/png")).to eq "<link rel=\"apple-touch-icon\" type=\"image/png\" href=\"/packs/static/nested/mb-icon-c38deda30895059837cf.png\" />"
+      expect(favicon_pack_tag("static/nested/mb-icon.png", rel: "apple-touch-icon", type: "image/png")).to eq "<link rel=\"apple-touch-icon\" type=\"image/png\" href=\"/packs/static/nested/mb-icon-c38deda30895059837cf.png\" />"
+    end
+
+    it "#preload_pack_asset generates correct tag" do
+      if self.class.method_defined?(:preload_link_tag)
+        expect(preload_pack_asset("fonts/fa-regular-400.woff2")).to eq %(<link rel="preload" href="/packs/fonts/fa-regular-400-944fb546bd7018b07190a32244f67dc9.woff2" as="font" type="font/woff2" crossorigin="anonymous">)
+      else
+        expect { preload_pack_asset("fonts/fa-regular-400.woff2") }.to raise_error "You need Rails >= 5.2 to use this tag."
+      end
+    end
+
+    it "#javascript_pack_tag generates correct tags" do
+      expected = <<~HTML.chomp
+        <script src="/packs/vendors~application~bootstrap-c20632e7baf2c81200d3.chunk.js" defer="defer"></script>
+        <script src="/packs/vendors~application-e55f2aae30c07fb6d82a.chunk.js" defer="defer"></script>
+        <script src="/packs/application-k344a6d59eef8632c9d1.js" defer="defer"></script>
+        <script src="/packs/bootstrap-300631c4f0e0f9c865bc.js" defer="defer"></script>
+      HTML
+
+      expect(javascript_pack_tag("application", "bootstrap")).to eq expected
+    end
+
+    it "#javascript_pack_tag generates correct tags by passing `defer: false`" do
+      expected = <<~HTML.chomp
+        <script src="/packs/vendors~application~bootstrap-c20632e7baf2c81200d3.chunk.js"></script>
+        <script src="/packs/vendors~application-e55f2aae30c07fb6d82a.chunk.js"></script>
+        <script src="/packs/application-k344a6d59eef8632c9d1.js"></script>
+        <script src="/packs/bootstrap-300631c4f0e0f9c865bc.js"></script>
+      HTML
+
+      expect(javascript_pack_tag("application", "bootstrap", defer: false)).to eq expected
+    end
+
+    it "#javascript_pack_tag generates correct appended tag" do
+      append_javascript_pack_tag("bootstrap", defer: false)
+
+      expected = <<~HTML.chomp
+        <script src="/packs/vendors~application~bootstrap-c20632e7baf2c81200d3.chunk.js" defer="defer"></script>
+        <script src="/packs/vendors~application-e55f2aae30c07fb6d82a.chunk.js" defer="defer"></script>
+        <script src="/packs/application-k344a6d59eef8632c9d1.js" defer="defer"></script>
+        <script src="/packs/bootstrap-300631c4f0e0f9c865bc.js"></script>
+      HTML
+
+      expect(javascript_pack_tag("application")).to eq expected
+    end
+
+    it "#javascript_pack_tag generates correct prepended tag" do
+      append_javascript_pack_tag("bootstrap")
+      prepend_javascript_pack_tag("main")
+
+      expected = <<~HTML.chomp
+        <script src="/packs/main-e323a53c7f30f5d53cbb.js" defer="defer"></script>
+        <script src="/packs/bootstrap-300631c4f0e0f9c865bc.js" defer="defer"></script>
+        <script src="/packs/vendors~application~bootstrap-c20632e7baf2c81200d3.chunk.js" defer="defer"></script>
+        <script src="/packs/vendors~application-e55f2aae30c07fb6d82a.chunk.js" defer="defer"></script>
+        <script src="/packs/application-k344a6d59eef8632c9d1.js" defer="defer"></script>
+      HTML
+
+      expect(javascript_pack_tag("application")).to eq expected
+    end
+
+    it "#append_javascript_pack_tag raises error if called after calling #javascript_pack_tag" do
+      expected_error_message = \
+        "You can only call append_javascript_pack_tag before javascript_pack_tag helper. " +
+        "Please refer to https://github.com/shakacode/shakapacker/blob/master/README.md#view-helper-append_javascript_pack_tag-prepend_javascript_pack_tag-and-append_stylesheet_pack_tag for the usage guide"
+
+      expect {
+        javascript_pack_tag("application")
+        append_javascript_pack_tag("bootstrap", defer: false)
+      }.to raise_error(expected_error_message)
+    end
+
+    it "#prepend_javascript_pack_tag raises error if called after calling #javascript_pack_tag" do
+      expected_error_message = \
+        "You can only call prepend_javascript_pack_tag before javascript_pack_tag helper. " +
+        "Please refer to https://github.com/shakacode/shakapacker/blob/master/README.md#view-helper-append_javascript_pack_tag-prepend_javascript_pack_tag-and-append_stylesheet_pack_tag for the usage guide"
+
+      expect {
+        javascript_pack_tag("application")
+        prepend_javascript_pack_tag("bootstrap", defer: false)
+      }.to raise_error(expected_error_message)
+    end
+
+    it "#javascript_pack_tag generates correct tags by passing `defer: true`" do
+      expected = <<~HTML.chomp
+        <script src="/packs/vendors~application~bootstrap-c20632e7baf2c81200d3.chunk.js" defer="defer"></script>
+        <script src="/packs/vendors~application-e55f2aae30c07fb6d82a.chunk.js" defer="defer"></script>
+        <script src="/packs/application-k344a6d59eef8632c9d1.js" defer="defer"></script>
+      HTML
+
+      expect(javascript_pack_tag("application", defer: true)).to eq expected
+    end
+
+    it "#javascript_pack_tag generates correct tags by passing symbol" do
+      expected = <<~HTML.chomp
+        <script src="/packs/vendors~application~bootstrap-c20632e7baf2c81200d3.chunk.js" defer="defer"></script>
+        <script src="/packs/vendors~application-e55f2aae30c07fb6d82a.chunk.js" defer="defer"></script>
+        <script src="/packs/application-k344a6d59eef8632c9d1.js" defer="defer"></script>
+      HTML
+
+      expect(javascript_pack_tag(:application)).to eq expected
+    end
+
+    it "#javascript_pack_tag rases error on multiple invocations" do
+      expected_error_message = "To prevent duplicated chunks on the page, you should call javascript_pack_tag only once on the page. " +
+      "Please refer to https://github.com/shakacode/shakapacker/blob/master/README.md#view-helpers-javascript_pack_tag-and-stylesheet_pack_tag for the usage guide"
+
+      expect {
+        javascript_pack_tag(:application)
+        javascript_pack_tag(:bootstrap)
+      }.to raise_error(expected_error_message)
+    end
+
+    it "#stylesheet_pack_tag generates correct link tag with string arguments" do
+      expected = (application_stylesheet_chunks + hello_stimulus_stylesheet_chunks)
+        .uniq
+        .map { |chunk| stylesheet_link_tag(chunk) }
+        .join("\n")
+
+      expect(stylesheet_pack_tag("application", "hello_stimulus")).to eq expected
+    end
+
+    it "#stylesheet_pack_tag generates correct link tag with symbol arguments" do
+      expected = (application_stylesheet_chunks + hello_stimulus_stylesheet_chunks)
+        .uniq
+        .map { |chunk| stylesheet_link_tag(chunk) }
+        .join("\n")
+
+      expect(stylesheet_pack_tag(:application, :hello_stimulus)).to eq expected
+    end
+
+    it "#stylesheet_pack_tag generates correct link tag with mixed arguments" do
+      expected = (application_stylesheet_chunks)
+        .map { |chunk| stylesheet_link_tag(chunk, media: "all") }
+        .join("\n")
+
+      expect(stylesheet_pack_tag("application", media: "all")).to eq expected
+    end
+
+    it "#stylesheet_pack_tag allows multiple invocations" do
+      app_style = stylesheet_pack_tag(:application)
+      stimulus_style = stylesheet_pack_tag(:hello_stimulus)
+
+      expect(app_style).to eq application_stylesheet_chunks.map { |chunk| stylesheet_link_tag(chunk) }.join("\n")
+
+      expect(stimulus_style).to eq hello_stimulus_stylesheet_chunks.map { |chunk| stylesheet_link_tag(chunk) }.join("\n")
+
+      expect {
+        stylesheet_pack_tag(:application)
+        stylesheet_pack_tag(:hello_stimulus)
+      }.to_not raise_error
+    end
+
+    it "#stylesheet_pack_tag appends" do
+      append_stylesheet_pack_tag(:hello_stimulus)
+
+      expect(stylesheet_pack_tag(:application)).to eq \
+        (application_stylesheet_chunks + hello_stimulus_stylesheet_chunks).uniq.map { |chunk| stylesheet_link_tag(chunk) }.join("\n")
+    end
+
+    it "#stylesheet_pack_tag appends duplicate" do
+      append_stylesheet_pack_tag(:hello_stimulus)
+      append_stylesheet_pack_tag(:application)
+
+      expect(stylesheet_pack_tag(:application)).to eq \
+        (application_stylesheet_chunks + hello_stimulus_stylesheet_chunks).uniq.map { |chunk| stylesheet_link_tag(chunk) }.join("\n")
+    end
+
+    it "#stylesheet_pack_tag supports multiple invocations with different media attr" do
+      app_style = stylesheet_pack_tag(:application)
+      app_style_with_media = stylesheet_pack_tag(:application, media: "print")
+      hello_stimulus_style_with_media = stylesheet_pack_tag(:hello_stimulus, media: "all")
+
+      expect(app_style).to eq application_stylesheet_chunks.map { |chunk| stylesheet_link_tag(chunk) }.join("\n")
+      expect(app_style_with_media).to eq application_stylesheet_chunks.map { |chunk| stylesheet_link_tag(chunk, media: "print") }.join("\n")
+      expect(hello_stimulus_style_with_media).to eq hello_stimulus_stylesheet_chunks.map { |chunk| stylesheet_link_tag(chunk, media: "all") }.join("\n")
+    end
+  end
+end
diff --git a/spec/backward_compatibility_specs/instance_spec_bc.rb b/spec/backward_compatibility_specs/instance_spec_bc.rb
new file mode 100644
index 000000000..8375b6ff5
--- /dev/null
+++ b/spec/backward_compatibility_specs/instance_spec_bc.rb
@@ -0,0 +1,31 @@
+require_relative "spec_helper_initializer"
+
+describe "Webpacker::Instance" do
+  before :each do
+    ENV.delete("WEBPACKER_CONFIG")
+    ENV.delete("SHAKAPACKER_CONFIG")
+    Webpacker.instance = Webpacker::Instance.new
+  end
+
+  after :each do
+    ENV.delete("WEBPACKER_CONFIG")
+    ENV.delete("SHAKAPACKER_CONFIG")
+    Webpacker.instance = Webpacker::Instance.new
+  end
+
+  it "uses default config path if no env variable defined" do
+    actual_config_path = Rails.root.join("config/webpacker.yml")
+    expected_config_path = Webpacker.config.config_path
+
+    expect(expected_config_path).to eq(actual_config_path)
+  end
+
+  it "uses WEBPACKER_CONFIG env variable for config file" do
+    ENV["WEBPACKER_CONFIG"] = "/some/random/path.yml"
+
+    actual_config_path = "/some/random/path.yml"
+    expected_config_path = Webpacker.config.config_path.to_s
+
+    expect(Webpacker.config.config_path.to_s).to eq("/some/random/path.yml")
+  end
+end
diff --git a/spec/backward_compatibility_specs/manifest_spec_bc.rb b/spec/backward_compatibility_specs/manifest_spec_bc.rb
new file mode 100644
index 000000000..eee46178a
--- /dev/null
+++ b/spec/backward_compatibility_specs/manifest_spec_bc.rb
@@ -0,0 +1,100 @@
+require_relative "spec_helper_initializer"
+
+describe "Webpacker::Manifest" do
+  let(:manifest_path) { File.expand_path File.join(File.dirname(__FILE__), "webpacker_test_app/public/packs", "manifest.json").to_s }
+
+  it "#lookup! throws exception for a non-existing asset file" do
+    asset_file = "calendar.js"
+    expected_error_message = "Shakapacker can't find #{asset_file} in #{manifest_path}"
+
+    allow(Webpacker.config).to receive(:compile?).and_return(false)
+
+    expect {
+      Webpacker.manifest.lookup!(asset_file)
+    }.to raise_error(Webpacker::Manifest::MissingEntryError, /#{expected_error_message}/)
+  end
+
+  it "#lookup! throws exception for a non-existing asset file with type and without extension" do
+    asset_file = "calendar"
+    expected_error_message = "Shakapacker can't find #{asset_file}.js in #{manifest_path}"
+
+    allow(Webpacker.config).to receive(:compile?).and_return(false)
+
+    expect {
+      Webpacker.manifest.lookup!(asset_file, type: :javascript)
+    }.to raise_error(Webpacker::Manifest::MissingEntryError, /#{expected_error_message}/)
+  end
+
+  it "#lookup! returns path to bundled bootstrap.js" do
+    actual = Webpacker.manifest.lookup!("bootstrap.js")
+    expected = "/packs/bootstrap-300631c4f0e0f9c865bc.js"
+
+    expect(actual).to eq expected
+  end
+
+  it "#lookup_pack_with_chunks! returns array of path to bundled bootstrap with type of javascript" do
+    actual = Webpacker.manifest.lookup_pack_with_chunks!("bootstrap", type: :javascript)
+    expected = ["/packs/bootstrap-300631c4f0e0f9c865bc.js"]
+
+    expect(actual).to eq expected
+  end
+
+  it "#lookup_with_chunks! returns array of path to bundled bootstrap.js with type of javascript" do
+    actual = Webpacker.manifest.lookup_pack_with_chunks!("bootstrap.js", type: :javascript)
+    expected = ["/packs/bootstrap-300631c4f0e0f9c865bc.js"]
+
+    expect(actual).to eq expected
+  end
+
+  it "#lookup_with_chunks! returns array of path to bundled 'print/application' without extension and in a sub-directory" do
+    actual = Webpacker.manifest.lookup_pack_with_chunks!("print/application", type: :css)
+    expected = ["/packs/print/application-983b6c164a47f7ed49cd.css"]
+
+    expect(actual).to eq expected
+  end
+
+  it "#lookup_with_chunks! returns array of path to bundled 'print/application.css' in a sub-directory" do
+    actual = Webpacker.manifest.lookup_pack_with_chunks!("print/application.css", type: :css)
+    expected = ["/packs/print/application-983b6c164a47f7ed49cd.css"]
+
+    expect(actual).to eq expected
+  end
+
+  it "#lookup returns nil for non-existing asset file" do
+    expect(Webpacker.manifest.lookup("foo.js")).to be nil
+  end
+
+  it "#lookup_pack_with_chunks returns nil for non-existing asset file" do
+    expect(Webpacker.manifest.lookup_pack_with_chunks("foo.js")).to be nil
+  end
+
+  it "#lookup returns path for bootstrap.js" do
+    actual = Webpacker.manifest.lookup("bootstrap.js")
+    expected = "/packs/bootstrap-300631c4f0e0f9c865bc.js"
+
+    expect(actual).to eq expected
+  end
+
+  it "#lookup_pack_with_chunks! throws exception for a non-existing asset file" do
+    asset_file = "calendar"
+
+    expected_error_message = "Shakapacker can't find #{asset_file}.js in #{manifest_path}"
+
+    allow(Webpacker.config).to receive(:compile?).and_return(false)
+
+    expect {
+      Webpacker.manifest.lookup_pack_with_chunks!(asset_file, type: :javascript)
+    }.to raise_error(Shakapacker::Manifest::MissingEntryError, /#{expected_error_message}/)
+  end
+
+  it "#lookup_pack_with_chunks! returns array of paths to bundled js files with 'application' in their name" do
+    actual_application_entrypoints = Webpacker.manifest.lookup_pack_with_chunks!("application", type: :javascript)
+    expected_application_entrypoints = [
+      "/packs/vendors~application~bootstrap-c20632e7baf2c81200d3.chunk.js",
+      "/packs/vendors~application-e55f2aae30c07fb6d82a.chunk.js",
+      "/packs/application-k344a6d59eef8632c9d1.js"
+    ]
+
+    expect(actual_application_entrypoints).to eq expected_application_entrypoints
+  end
+end
diff --git a/spec/backward_compatibility_specs/mtime_strategy_spec_bc.rb b/spec/backward_compatibility_specs/mtime_strategy_spec_bc.rb
new file mode 100644
index 000000000..4adfaa23e
--- /dev/null
+++ b/spec/backward_compatibility_specs/mtime_strategy_spec_bc.rb
@@ -0,0 +1,55 @@
+require_relative "spec_helper_initializer"
+
+describe "Webpacker::MtimeStrategy" do
+  let(:mtime_strategy) { Webpacker::MtimeStrategy.new }
+  let(:manifest_timestamp) { Time.parse("2021-01-01 12:34:56 UTC") }
+
+  describe "#fresh?" do
+    it "returns false when manifest is missing" do
+      latest_timestamp = manifest_timestamp + 3600
+
+      with_stubs(latest_timestamp: latest_timestamp.to_i, manifest_exists: false) do
+        expect(mtime_strategy.fresh?).to be false
+      end
+    end
+
+    it "returns false when manifest is older" do
+      latest_timestamp = manifest_timestamp + 3600
+
+      with_stubs(latest_timestamp: latest_timestamp.to_i) do
+        expect(mtime_strategy.fresh?).to be false
+      end
+    end
+
+    it "returns true when manifest is new" do
+      latest_timestamp = manifest_timestamp - 3600
+
+      with_stubs(latest_timestamp: latest_timestamp.to_i) do
+        expect(mtime_strategy.fresh?).to be true
+      end
+    end
+  end
+
+  describe "#stale?" do
+    it "returns false when #fresh? is true" do
+      expect(mtime_strategy).to receive(:fresh?).and_return(true)
+
+      expect(mtime_strategy.stale?).to be false
+    end
+
+    it "returns true when #fresh? is false" do
+      expect(mtime_strategy).to receive(:fresh?).and_return(false)
+
+      expect(mtime_strategy.stale?).to be true
+    end
+  end
+
+  private
+
+    def with_stubs(latest_timestamp:, manifest_exists: true)
+      allow(mtime_strategy).to receive(:latest_modified_timestamp).and_return(latest_timestamp)
+      allow(FileTest).to receive(:exist?).and_return(manifest_exists)
+      allow(File).to receive(:mtime).and_return(manifest_timestamp)
+      yield
+    end
+end
diff --git a/spec/backward_compatibility_specs/rake_tasks_spec_bc.rb b/spec/backward_compatibility_specs/rake_tasks_spec_bc.rb
new file mode 100644
index 000000000..b782b0937
--- /dev/null
+++ b/spec/backward_compatibility_specs/rake_tasks_spec_bc.rb
@@ -0,0 +1,37 @@
+require_relative "spec_helper_initializer"
+
+describe "RakeTasks" do
+  let(:test_app_path) { File.expand_path("webpacker_test_app", __dir__) }
+
+  it "`rake -T` lists Webpacker tasks" do
+    output = Dir.chdir(test_app_path) { `rake -T` }
+    expect(output).to match /webpacker .+DEPRECATED/
+    expect(output).to match /webpacker:check_binstubs.+DEPRECATED/
+    expect(output).to match /webpacker:check_node.+DEPRECATED/
+    expect(output).to match /webpacker:check_yarn.+DEPRECATED/
+    expect(output).to match /webpacker:clean.+DEPRECATED/
+    expect(output).to match /webpacker:clobber.+DEPRECATED/
+    expect(output).to match /webpacker:compile.+DEPRECATED/
+    expect(output).to match /webpacker:install.+DEPRECATED/
+    expect(output).to match /webpacker:verify_install.+DEPRECATED/
+  end
+
+  it "`webpacker:check_binstubs` doesn't get 'webpack binstub not found' error" do
+    output = Dir.chdir(test_app_path) { `rake webpacker:check_binstubs 2>&1` }
+    expect(output).to_not include "webpack binstub not found."
+    expect(output).to include "DEPRECATION"
+  end
+
+  it "`webpacker:check_node` doesn't get 'webpacker requires Node.js' error" do
+    output = Dir.chdir(test_app_path) { `rake webpacker:check_node 2>&1` }
+    expect(output).to_not include "Shakapacker requires Node.js"
+    expect(output).to include "DEPRECATION"
+  end
+
+  it "`webpacker:check_yarn` doesn't get error related to yarn" do
+    output = Dir.chdir(test_app_path) { `rake webpacker:check_yarn 2>&1` }
+    expect(output).to_not include "Yarn not installed"
+    expect(output).to_not include "Shakapacker requires Yarn"
+    expect(output).to include "DEPRECATION"
+  end
+end
diff --git a/spec/backward_compatibility_specs/spec_helper_initializer.rb b/spec/backward_compatibility_specs/spec_helper_initializer.rb
new file mode 100644
index 000000000..42426bb59
--- /dev/null
+++ b/spec/backward_compatibility_specs/spec_helper_initializer.rb
@@ -0,0 +1,24 @@
+require_relative "webpacker_test_app/config/environment"
+
+Rails.env = "production"
+
+Webpacker.instance = ::Webpacker::Instance.new
+
+def reloaded_config
+  Webpacker.instance.instance_variable_set(:@env, nil)
+  Webpacker.instance.instance_variable_set(:@config, nil)
+  Webpacker.instance.instance_variable_set(:@dev_server, nil)
+  Webpacker.env
+  Webpacker.config
+  Webpacker.dev_server
+end
+
+def with_rails_env(env)
+  original = Rails.env
+  Rails.env = ActiveSupport::StringInquirer.new(env)
+  reloaded_config
+  yield
+ensure
+  Rails.env = ActiveSupport::StringInquirer.new(original)
+  reloaded_config
+end
diff --git a/spec/backward_compatibility_specs/webpack_runner_spec_bc.rb b/spec/backward_compatibility_specs/webpack_runner_spec_bc.rb
new file mode 100644
index 000000000..c7ea5ada2
--- /dev/null
+++ b/spec/backward_compatibility_specs/webpack_runner_spec_bc.rb
@@ -0,0 +1,56 @@
+require_relative "spec_helper_initializer"
+# Requiring from webpacker directory to ensure old ./bin/webpacker-dev-server works fine
+require "webpacker/webpack_runner"
+
+describe "WebpackRunner" do
+  before :all do
+    @original_node_env, ENV["NODE_ENV"] = ENV["NODE_ENV"], "development"
+    @original_rails_env, ENV["RAILS_ENV"] = ENV["RAILS_ENV"], "development"
+  end
+
+  after :all do
+    ENV["NODE_ENV"] = @original_node_env
+    ENV["RAILS_ENV"] = @original_rails_env
+  end
+
+  it "runs cmd via node_modules" do
+    cmd = ["#{test_app_path}/node_modules/.bin/webpack", "--config", "#{test_app_path}/config/webpack/webpack.config.js"]
+
+    verify_command(cmd, use_node_modules: true)
+  end
+
+  it "runs cmd via yarn" do
+    cmd = ["yarn", "webpack", "--config", "#{test_app_path}/config/webpack/webpack.config.js"]
+
+    verify_command(cmd, use_node_modules: false)
+  end
+
+  it "runs cmd argv" do
+    cmd = ["#{test_app_path}/node_modules/.bin/webpack", "--config", "#{test_app_path}/config/webpack/webpack.config.js", "--watch"]
+
+    verify_command(cmd, argv: ["--watch"])
+  end
+
+  private
+    def test_app_path
+      File.expand_path("webpacker_test_app", __dir__)
+    end
+
+    def verify_command(cmd, use_node_modules: true, argv: [])
+      cwd = Dir.pwd
+      Dir.chdir(test_app_path)
+
+      klass = Webpacker::WebpackRunner
+      instance = klass.new(argv)
+
+      allow(klass).to receive(:new).and_return(instance)
+      allow(instance).to receive(:node_modules_bin_exist?).and_return(use_node_modules)
+      allow(Kernel).to receive(:exec)
+
+      klass.run(argv)
+
+      expect(Kernel).to have_received(:exec).with(Webpacker::Compiler.env, *cmd)
+    ensure
+      Dir.chdir(cwd)
+    end
+end
diff --git a/spec/backward_compatibility_specs/webpacker_spec_bc.rb b/spec/backward_compatibility_specs/webpacker_spec_bc.rb
new file mode 100644
index 000000000..9dcdff4fb
--- /dev/null
+++ b/spec/backward_compatibility_specs/webpacker_spec_bc.rb
@@ -0,0 +1,41 @@
+require_relative "spec_helper_initializer"
+
+describe "webpacker" do
+  describe "#inline_css?" do
+    let(:dev_server) { instance_double("Webpacker::DevServer") }
+
+    before :each do
+      allow(dev_server).to receive(:host).and_return("localhost")
+      allow(dev_server).to receive(:port).and_return("3035")
+      allow(dev_server).to receive(:pretty?).and_return(false)
+      allow(dev_server).to receive(:https?).and_return(true)
+      allow(dev_server).to receive(:running?).and_return(true)
+    end
+
+    it "returns nil with disabled dev_server" do
+      expect(Webpacker.inlining_css?).to be nil
+    end
+
+    it "returns true with enabled hmr" do
+      allow(dev_server).to receive(:hmr?).and_return(true)
+      allow(dev_server).to receive(:inline_css?).and_return(true)
+
+      allow(Webpacker.instance).to receive(:dev_server).and_return(dev_server)
+
+      expect(Webpacker.inlining_css?).to be true
+    end
+
+    it "returns false with enabled hmr and explicitly setting inline_css to false" do
+      allow(dev_server).to receive(:hmr?).and_return(true)
+      allow(dev_server).to receive(:inline_css?).and_return(false)
+
+      allow(Webpacker.instance).to receive(:dev_server).and_return(dev_server)
+
+      expect(Webpacker.inlining_css?).to be false
+    end
+  end
+
+  it "has app_autoload_paths cleanup" do
+    expect($test_app_autoload_paths_in_initializer).to eq []
+  end
+end
diff --git a/spec/backward_compatibility_specs/webpacker_test_app/.gitignore b/spec/backward_compatibility_specs/webpacker_test_app/.gitignore
new file mode 100644
index 000000000..e8cd2e2fd
--- /dev/null
+++ b/spec/backward_compatibility_specs/webpacker_test_app/.gitignore
@@ -0,0 +1,2 @@
+log/
+tmp/
diff --git a/spec/backward_compatibility_specs/webpacker_test_app/Rakefile b/spec/backward_compatibility_specs/webpacker_test_app/Rakefile
new file mode 100644
index 000000000..d1baef069
--- /dev/null
+++ b/spec/backward_compatibility_specs/webpacker_test_app/Rakefile
@@ -0,0 +1,3 @@
+require_relative "config/application"
+
+Rails.application.load_tasks
diff --git a/spec/backward_compatibility_specs/webpacker_test_app/app/packs/entrypoints/application.js b/spec/backward_compatibility_specs/webpacker_test_app/app/packs/entrypoints/application.js
new file mode 100644
index 000000000..0ce89b488
--- /dev/null
+++ b/spec/backward_compatibility_specs/webpacker_test_app/app/packs/entrypoints/application.js
@@ -0,0 +1,10 @@
+/* eslint no-console:0 */
+// This file is automatically compiled by Webpack, along with any other files
+// present in this directory. You're encouraged to place your actual application logic in
+// a relevant structure within app/packs and only use these pack files to reference
+// that code so it'll be compiled.
+//
+// To reference this file, add <%= javascript_pack_tag 'application' %> to the appropriate
+// layout file, like app/views/layouts/application.html.erb
+
+console.log('Hello World from shakapacker')
diff --git a/spec/backward_compatibility_specs/webpacker_test_app/app/packs/entrypoints/generated/something.js b/spec/backward_compatibility_specs/webpacker_test_app/app/packs/entrypoints/generated/something.js
new file mode 100644
index 000000000..90c6f94e3
--- /dev/null
+++ b/spec/backward_compatibility_specs/webpacker_test_app/app/packs/entrypoints/generated/something.js
@@ -0,0 +1,2 @@
+/* eslint no-console:0 */
+console.log('entrypoints/nested/something')
diff --git a/spec/backward_compatibility_specs/webpacker_test_app/app/packs/entrypoints/multi_entry.css b/spec/backward_compatibility_specs/webpacker_test_app/app/packs/entrypoints/multi_entry.css
new file mode 100644
index 000000000..54b560f84
--- /dev/null
+++ b/spec/backward_compatibility_specs/webpacker_test_app/app/packs/entrypoints/multi_entry.css
@@ -0,0 +1,4 @@
+/*
+ * Dummy file #1 for Multi File Entry points: https://webpack.js.org/guides/entry-advanced/
+ * This file must be named the same
+ */
\ No newline at end of file
diff --git a/spec/backward_compatibility_specs/webpacker_test_app/app/packs/entrypoints/multi_entry.js b/spec/backward_compatibility_specs/webpacker_test_app/app/packs/entrypoints/multi_entry.js
new file mode 100644
index 000000000..9fea9c084
--- /dev/null
+++ b/spec/backward_compatibility_specs/webpacker_test_app/app/packs/entrypoints/multi_entry.js
@@ -0,0 +1,4 @@
+/*
+ * Dummy file #2 for Multi File Entry points: https://webpack.js.org/guides/entry-advanced/
+ * This file must be named the same
+ */
diff --git a/lib/install/bin/webpacker b/spec/backward_compatibility_specs/webpacker_test_app/bin/webpacker
old mode 100755
new mode 100644
similarity index 100%
rename from lib/install/bin/webpacker
rename to spec/backward_compatibility_specs/webpacker_test_app/bin/webpacker
diff --git a/lib/install/bin/webpacker-dev-server b/spec/backward_compatibility_specs/webpacker_test_app/bin/webpacker-dev-server
similarity index 100%
rename from lib/install/bin/webpacker-dev-server
rename to spec/backward_compatibility_specs/webpacker_test_app/bin/webpacker-dev-server
diff --git a/spec/backward_compatibility_specs/webpacker_test_app/config.ru b/spec/backward_compatibility_specs/webpacker_test_app/config.ru
new file mode 100644
index 000000000..8987d1c00
--- /dev/null
+++ b/spec/backward_compatibility_specs/webpacker_test_app/config.ru
@@ -0,0 +1,5 @@
+# This file allows the `Rails.root` to be correctly determined.
+
+require_relative "config/environment"
+
+run Rails.application
diff --git a/spec/backward_compatibility_specs/webpacker_test_app/config/application.rb b/spec/backward_compatibility_specs/webpacker_test_app/config/application.rb
new file mode 100644
index 000000000..069f27bee
--- /dev/null
+++ b/spec/backward_compatibility_specs/webpacker_test_app/config/application.rb
@@ -0,0 +1,11 @@
+require "action_controller/railtie"
+require "action_view/railtie"
+require "shakapacker"
+
+module WebpackerTestApp
+  class Application < ::Rails::Application
+    config.secret_key_base = "abcdef"
+    config.eager_load = true
+    config.active_support.test_order = :sorted
+  end
+end
diff --git a/spec/backward_compatibility_specs/webpacker_test_app/config/environment.rb b/spec/backward_compatibility_specs/webpacker_test_app/config/environment.rb
new file mode 100644
index 000000000..3eb71cb46
--- /dev/null
+++ b/spec/backward_compatibility_specs/webpacker_test_app/config/environment.rb
@@ -0,0 +1,4 @@
+require_relative "application"
+
+Rails.backtrace_cleaner.remove_silencers!
+Rails.application.initialize!
diff --git a/spec/backward_compatibility_specs/webpacker_test_app/config/initializers/inspect_autoload_paths.rb b/spec/backward_compatibility_specs/webpacker_test_app/config/initializers/inspect_autoload_paths.rb
new file mode 100644
index 000000000..56c65f178
--- /dev/null
+++ b/spec/backward_compatibility_specs/webpacker_test_app/config/initializers/inspect_autoload_paths.rb
@@ -0,0 +1 @@
+$test_app_autoload_paths_in_initializer = ActiveSupport::Dependencies.autoload_paths
diff --git a/spec/backward_compatibility_specs/webpacker_test_app/config/webpack/webpack.config.js b/spec/backward_compatibility_specs/webpacker_test_app/config/webpack/webpack.config.js
new file mode 100644
index 000000000..e69de29bb
diff --git a/spec/test_app/config/webpacker.yml b/spec/backward_compatibility_specs/webpacker_test_app/config/webpacker.yml
similarity index 94%
rename from spec/test_app/config/webpacker.yml
rename to spec/backward_compatibility_specs/webpacker_test_app/config/webpacker.yml
index 712fcd42b..a51f2dba2 100644
--- a/spec/test_app/config/webpacker.yml
+++ b/spec/backward_compatibility_specs/webpacker_test_app/config/webpacker.yml
@@ -1,7 +1,7 @@
-# Note: You must restart bin/webpacker-dev-server for changes to take effect
+# Note: You must restart bin/shakapacker-dev-server for changes to take effect
 
 default: &default
-  source_path: app/javascript
+  source_path: app/packs
   source_entry_path: entrypoints
   nested_entries: false
   public_root_path: public
diff --git a/spec/test_app/config/webpacker_css_extract_ignore_order_warnings.yml b/spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_css_extract_ignore_order_warnings.yml
similarity index 94%
rename from spec/test_app/config/webpacker_css_extract_ignore_order_warnings.yml
rename to spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_css_extract_ignore_order_warnings.yml
index 171e52597..1d10eb492 100644
--- a/spec/test_app/config/webpacker_css_extract_ignore_order_warnings.yml
+++ b/spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_css_extract_ignore_order_warnings.yml
@@ -1,7 +1,7 @@
-# Note: You must restart bin/webpacker-dev-server for changes to take effect
+# Note: You must restart bin/shakapacker-dev-server for changes to take effect
 
 default: &default
-  source_path: app/javascript
+  source_path: app/packs
   source_entry_path: entrypoints
   nested_entries: true
   public_root_path: public
diff --git a/spec/test_app/config/webpacker_defaults_fallback.yml b/spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_defaults_fallback.yml
similarity index 66%
rename from spec/test_app/config/webpacker_defaults_fallback.yml
rename to spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_defaults_fallback.yml
index 5575fdd34..3bb2ac526 100644
--- a/spec/test_app/config/webpacker_defaults_fallback.yml
+++ b/spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_defaults_fallback.yml
@@ -1,4 +1,4 @@
-# Note: You must restart bin/webpacker-dev-server for changes to take effect
+# Note: You must restart bin/shakapacker-dev-server for changes to take effect
 
 default: &default
   # cache_manifest will be fetched from bundled defaults
diff --git a/spec/test_app/config/webpacker_manifest_path.yml b/spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_manifest_path.yml
similarity index 95%
rename from spec/test_app/config/webpacker_manifest_path.yml
rename to spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_manifest_path.yml
index b945e6263..facf53e85 100644
--- a/spec/test_app/config/webpacker_manifest_path.yml
+++ b/spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_manifest_path.yml
@@ -1,7 +1,7 @@
 # Note: You must restart bin/webpack-dev-server for changes to take effect
 
 default: &default
-  source_path: app/javascript
+  source_path: app/packs
   source_entry_path: entrypoints
   public_root_path: public
   public_output_path: packs
@@ -9,7 +9,7 @@ default: &default
   webpack_compile_output: false
 
   # Location for manifest.json, defaults to {public_output_path}/manifest.json if unset
-  manifest_path: app/javascript/manifest.json
+  manifest_path: app/packs/manifest.json
 
   # Additional paths webpack should look up modules
   # ['app/assets', 'engine/foo/app/assets']
diff --git a/spec/test_app/config/webpacker_nested_entries.yml b/spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_nested_entries.yml
similarity index 98%
rename from spec/test_app/config/webpacker_nested_entries.yml
rename to spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_nested_entries.yml
index 148ed91d5..5bec1cae8 100644
--- a/spec/test_app/config/webpacker_nested_entries.yml
+++ b/spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_nested_entries.yml
@@ -1,7 +1,7 @@
 # Note: You must restart bin/webpacker-dev-server for changes to take effect
 
 default: &default
-  source_path: app/javascript
+  source_path: app/packs
   source_entry_path: entrypoints
   nested_entries: true
   public_root_path: public
diff --git a/spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_no_precompile.yml b/spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_no_precompile.yml
new file mode 100644
index 000000000..9c265e644
--- /dev/null
+++ b/spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_no_precompile.yml
@@ -0,0 +1,7 @@
+# Note: You must restart bin/shakapacker-dev-server for changes to take effect
+
+default: &default
+  webpacker_precompile: false
+
+production:
+  <<: *default
diff --git a/spec/test_app/config/webpacker_other_location.yml b/spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_other_location.yml
similarity index 94%
rename from spec/test_app/config/webpacker_other_location.yml
rename to spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_other_location.yml
index 796f448ee..9e4360087 100644
--- a/spec/test_app/config/webpacker_other_location.yml
+++ b/spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_other_location.yml
@@ -1,7 +1,7 @@
-# Note: You must restart bin/webpacker-dev-server for changes to take effect
+# Note: You must restart bin/shakapacker-dev-server for changes to take effect
 
 default: &default
-  source_path: app/javascript
+  source_path: app/packs
   source_entry_path: entrypoints
   public_root_path: public
   public_output_path: packs
diff --git a/spec/test_app/config/webpacker_public_root.yml b/spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_public_root.yml
similarity index 74%
rename from spec/test_app/config/webpacker_public_root.yml
rename to spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_public_root.yml
index c83144778..701ae8752 100644
--- a/spec/test_app/config/webpacker_public_root.yml
+++ b/spec/backward_compatibility_specs/webpacker_test_app/config/webpacker_public_root.yml
@@ -1,4 +1,4 @@
-# Note: You must restart bin/webpacker-dev-server for changes to take effect
+# Note: You must restart bin/shakapacker-dev-server for changes to take effect
 
 default: &default
   public_root_path: ../public
diff --git a/spec/backward_compatibility_specs/webpacker_test_app/package.json b/spec/backward_compatibility_specs/webpacker_test_app/package.json
new file mode 100644
index 000000000..468fb4ac1
--- /dev/null
+++ b/spec/backward_compatibility_specs/webpacker_test_app/package.json
@@ -0,0 +1,13 @@
+{
+  "name": "webpacker_test_app",
+  "version": "1.0.0",
+  "main": "index.js",
+  "license": "MIT",
+  "private": true,
+  "dependencies": {
+    "left-pad": "^1.2.0"
+  },
+  "devDependencies": {
+    "right-pad": "^1.0.1"
+  }
+}
diff --git a/spec/backward_compatibility_specs/webpacker_test_app/public/packs/manifest.json b/spec/backward_compatibility_specs/webpacker_test_app/public/packs/manifest.json
new file mode 100644
index 000000000..f3fa445e8
--- /dev/null
+++ b/spec/backward_compatibility_specs/webpacker_test_app/public/packs/manifest.json
@@ -0,0 +1,58 @@
+{
+  "bootstrap.css": "/packs/bootstrap-c38deda30895059837cf.css",
+  "application.css": "/packs/application-dd6b1cd38bfa093df600.css",
+  "bootstrap.js": "/packs/bootstrap-300631c4f0e0f9c865bc.js",
+  "main.js": "/packs/main-e323a53c7f30f5d53cbb.js",
+  "application.js": "/packs/application-k344a6d59eef8632c9d1.js",
+  "application.png": "/packs/application-k344a6d59eef8632c9d1.png",
+  "fonts/fa-regular-400.woff2": "/packs/fonts/fa-regular-400-944fb546bd7018b07190a32244f67dc9.woff2",
+  "static/image.jpg": "/packs/static/image-c38deda30895059837cf.jpg",
+  "static/image-2x.jpg": "/packs/static/image-2x-7cca48e6cae66ec07b8e.jpg",
+  "static/nested/image.jpg": "/packs/static/nested/image-c38deda30895059837cf.jpg",
+  "static/mb-icon.png": "/packs/static/mb-icon-c38deda30895059837cf.png",
+  "static/nested/mb-icon.png": "/packs/static/nested/mb-icon-c38deda30895059837cf.png",
+  "entrypoints": {
+    "application": {
+      "assets": {
+        "js": [
+          "/packs/vendors~application~bootstrap-c20632e7baf2c81200d3.chunk.js",
+          "/packs/vendors~application-e55f2aae30c07fb6d82a.chunk.js",
+          "/packs/application-k344a6d59eef8632c9d1.js"
+        ],
+        "css": [
+          "/packs/1-c20632e7baf2c81200d3.chunk.css",
+          "/packs/application-k344a6d59eef8632c9d1.chunk.css"
+        ]
+      }
+    },
+    "bootstrap": {
+      "assets": {
+        "js": [
+          "/packs/bootstrap-300631c4f0e0f9c865bc.js"
+        ]
+      }
+    },
+    "main": {
+      "assets": {
+        "js": [
+          "/packs/main-e323a53c7f30f5d53cbb.js"
+        ]
+      }
+    },
+    "hello_stimulus": {
+      "assets": {
+        "css": [
+          "/packs/1-c20632e7baf2c81200d3.chunk.css",
+          "/packs/hello_stimulus-k344a6d59eef8632c9d1.chunk.css"
+        ]
+      }
+    },
+    "print/application": {
+      "assets": {
+        "css": [
+          "/packs/print/application-983b6c164a47f7ed49cd.css"
+        ]
+      }
+    }
+  }
+}
diff --git a/spec/backward_compatibility_specs/webpacker_test_app/some.config.js b/spec/backward_compatibility_specs/webpacker_test_app/some.config.js
new file mode 100644
index 000000000..e69de29bb
diff --git a/spec/backward_compatibility_specs/webpacker_test_app/tmp/shakapacker/last-compilation-digest-production b/spec/backward_compatibility_specs/webpacker_test_app/tmp/shakapacker/last-compilation-digest-production
new file mode 100644
index 000000000..5ec7c939d
--- /dev/null
+++ b/spec/backward_compatibility_specs/webpacker_test_app/tmp/shakapacker/last-compilation-digest-production
@@ -0,0 +1 @@
+70edce1bd3ecd60639ea9e56a3cd098a3641ca07
\ No newline at end of file
diff --git a/spec/backward_compatibility_specs/webpacker_test_app/yarn.lock b/spec/backward_compatibility_specs/webpacker_test_app/yarn.lock
new file mode 100644
index 000000000..b87ca6416
--- /dev/null
+++ b/spec/backward_compatibility_specs/webpacker_test_app/yarn.lock
@@ -0,0 +1,11 @@
+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+
+left-pad@^1.2.0:
+  version "1.2.0"
+  resolved "https://registry.yarnpkg.com/left-pad/-/left-pad-1.2.0.tgz#d30a73c6b8201d8f7d8e7956ba9616087a68e0ee"
+
+right-pad@^1.0.1:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/right-pad/-/right-pad-1.0.1.tgz#8ca08c2cbb5b55e74dafa96bf7fd1a27d568c8d0"
diff --git a/spec/command_spec.rb b/spec/command_spec.rb
index fa423eb1d..90b5d570c 100644
--- a/spec/command_spec.rb
+++ b/spec/command_spec.rb
@@ -1,27 +1,29 @@
+require_relative "spec_helper_initializer"
+
 describe "Command" do
   before do
-    allow(Webpacker.logger).to receive(:info)
+    allow(Shakapacker.logger).to receive(:info)
   end
 
   describe "#compile" do
     it "returns success status when stale" do
-      expect(Webpacker.compiler).to receive(:stale?).and_return(true)
-      expect(Webpacker.compiler).to receive(:run_webpack).and_return(true)
+      expect(Shakapacker.compiler).to receive(:stale?).and_return(true)
+      expect(Shakapacker.compiler).to receive(:run_webpack).and_return(true)
 
-      expect(Webpacker.commands.compile).to be true
+      expect(Shakapacker.commands.compile).to be true
     end
 
     it "returns success status when fresh" do
-      expect(Webpacker.compiler).to receive(:stale?).and_return(false)
+      expect(Shakapacker.compiler).to receive(:stale?).and_return(false)
 
-      expect(Webpacker.commands.compile).to be true
+      expect(Shakapacker.commands.compile).to be true
     end
 
     it "returns failure status when stale" do
-      expect(Webpacker.compiler).to receive(:stale?).and_return(true)
-      expect(Webpacker.compiler).to receive(:run_webpack).and_return(false)
+      expect(Shakapacker.compiler).to receive(:stale?).and_return(true)
+      expect(Shakapacker.compiler).to receive(:run_webpack).and_return(false)
 
-      expect(Webpacker.commands.compile).to be false
+      expect(Shakapacker.commands.compile).to be false
     end
   end
 
@@ -30,7 +32,7 @@
     let(:prev_files) do
       # Test assets to be kept and deleted, path and mtime
       {
-        # recent versions to be kept with Webpacker.commands.clean(count = 2)
+        # recent versions to be kept with Shakapacker.commands.clean(count = 2)
         "js/application-deadbeef.js" => now - 4000,
         "js/common-deadbeee.js" => now - 4002,
         "css/common-deadbeed.css" => now - 4004,
@@ -39,12 +41,12 @@
         "js/common-1eadbeee.js" => now - 8002,
         "css/common-1eadbeed.css" => now - 8004,
         "media/images/logo-1eadbeeb.css" => now - 8006,
-        # new files to be kept with Webpacker.commands.clean(age = 3600)
+        # new files to be kept with Shakapacker.commands.clean(age = 3600)
         "js/brandnew-0001.js" => now,
         "js/brandnew-0002.js" => now - 10,
         "js/brandnew-0003.js" => now - 20,
         "js/brandnew-0004.js" => now - 40,
-      }.transform_keys { |path| "#{Webpacker.config.public_output_path}/#{path}" }
+      }.transform_keys { |path| "#{Shakapacker.config.public_output_path}/#{path}" }
     end
 
     let(:expired_files) do
@@ -54,7 +56,7 @@
         "js/common-0eadbeee.js" => now - 9002,
         "css/common-0eadbeed.css" => now - 9004,
         "js/brandnew-0005.js" => now - 3640,
-      }.transform_keys { |path| "#{Webpacker.config.public_output_path}/#{path}" }
+      }.transform_keys { |path| "#{Shakapacker.config.public_output_path}/#{path}" }
     end
 
     let(:all_files) { prev_files.merge(expired_files) }
@@ -66,7 +68,7 @@
     before :context do
       @dir_glob_stub = Proc.new { |arg|
         case arg
-        when "#{Webpacker.config.public_output_path}/**/*"
+        when "#{Shakapacker.config.public_output_path}/**/*"
           all_files.keys
         else
           []
@@ -76,7 +78,7 @@
 
     it "works with nested hashes and without any compiled files" do
       allow(File).to receive(:delete).and_return(true)
-      expect(Webpacker.commands.clean).to be true
+      expect(Shakapacker.commands.clean).to be true
     end
 
     it "deletes only and only expired versioned files if no parameter passed" do
@@ -85,7 +87,7 @@
       end
 
       with_time_dir_and_files_stub do
-        expect(Webpacker.commands.clean).to be true
+        expect(Shakapacker.commands.clean).to be true
 
         # Verify that only and only expired files are deleted
         all_files.keys.each do |longpath|
diff --git a/spec/compiler_spec.rb b/spec/compiler_spec.rb
index 6388f4276..12a57973d 100644
--- a/spec/compiler_spec.rb
+++ b/spec/compiler_spec.rb
@@ -1,32 +1,34 @@
-describe "Webpacker::Compiler" do
+require_relative "spec_helper_initializer"
+
+describe "Shakapacker::Compiler" do
   it "accepts custom environment variables" do
-    expect(Webpacker.compiler.send(:webpack_env)["FOO"]).to be nil
+    expect(Shakapacker.compiler.send(:webpack_env)["FOO"]).to be nil
 
-    Webpacker.compiler.env["FOO"] = "BAR"
-    expect(Webpacker.compiler.send(:webpack_env)["FOO"]).to eq "BAR"
+    Shakapacker.compiler.env["FOO"] = "BAR"
+    expect(Shakapacker.compiler.send(:webpack_env)["FOO"]).to eq "BAR"
   ensure
-    Webpacker.compiler.env = {}
+    Shakapacker.compiler.env = {}
   end
 
   it "returns true when fresh" do
     mocked_strategy = double("Strategy")
     expect(mocked_strategy).to receive(:stale?).and_return(false)
 
-    expect(Webpacker.compiler).to receive(:strategy).and_return(mocked_strategy)
+    expect(Shakapacker.compiler).to receive(:strategy).and_return(mocked_strategy)
 
-    expect(Webpacker.compiler.compile).to be true
+    expect(Shakapacker.compiler.compile).to be true
   end
 
   it "returns true and calls after_compile_hook on successful compile" do
     mocked_strategy = spy("Strategy")
     expect(mocked_strategy).to receive(:stale?).and_return(true)
 
-    allow(Webpacker.compiler).to receive(:strategy).and_return(mocked_strategy)
+    allow(Shakapacker.compiler).to receive(:strategy).and_return(mocked_strategy)
 
     status = OpenStruct.new(success?: true)
     allow(Open3).to receive(:capture3).and_return([:sterr, :stdout, status])
 
-    expect(Webpacker.compiler.compile).to be true
+    expect(Shakapacker.compiler.compile).to be true
     expect(mocked_strategy).to have_received(:after_compile_hook)
   end
 
@@ -35,23 +37,23 @@
     allow(mocked_strategy).to receive(:stale?).and_return(true)
     allow(mocked_strategy).to receive(:after_compile_hook)
 
-    allow(Webpacker.compiler).to receive(:strategy).and_return(mocked_strategy)
+    allow(Shakapacker.compiler).to receive(:strategy).and_return(mocked_strategy)
 
     status = OpenStruct.new(success?: false)
     allow(Open3).to receive(:capture3).and_return([:sterr, :stdout, status])
 
-    expect(Webpacker.compiler.compile).to be false
+    expect(Shakapacker.compiler.compile).to be false
     expect(mocked_strategy).to have_received(:after_compile_hook)
   end
 
   it "accepts external env variables" do
-    expect(Webpacker.compiler.send(:webpack_env)["WEBPACKER_ASSET_HOST"]).to be nil
-    expect(Webpacker.compiler.send(:webpack_env)["WEBPACKER_RELATIVE_URL_ROOT"]).to be nil
+    expect(Shakapacker.compiler.send(:webpack_env)["SHAKAPACKER_ASSET_HOST"]).to be nil
+    expect(Shakapacker.compiler.send(:webpack_env)["SHAKAPACKER_RELATIVE_URL_ROOT"]).to be nil
 
-    ENV["WEBPACKER_ASSET_HOST"] = "foo.bar"
-    ENV["WEBPACKER_RELATIVE_URL_ROOT"] = "/baz"
+    ENV["SHAKAPACKER_ASSET_HOST"] = "foo.bar"
+    ENV["SHAKAPACKER_RELATIVE_URL_ROOT"] = "/baz"
 
-    expect(Webpacker.compiler.send(:webpack_env)["WEBPACKER_ASSET_HOST"]).to eq "foo.bar"
-    expect(Webpacker.compiler.send(:webpack_env)["WEBPACKER_RELATIVE_URL_ROOT"]).to eq "/baz"
+    expect(Shakapacker.compiler.send(:webpack_env)["SHAKAPACKER_ASSET_HOST"]).to eq "foo.bar"
+    expect(Shakapacker.compiler.send(:webpack_env)["SHAKAPACKER_RELATIVE_URL_ROOT"]).to eq "/baz"
   end
 end
diff --git a/spec/compiler_strategy_spec.rb b/spec/compiler_strategy_spec.rb
index c94ce19ea..779c56334 100644
--- a/spec/compiler_strategy_spec.rb
+++ b/spec/compiler_strategy_spec.rb
@@ -1,20 +1,22 @@
-describe "Webpacker::CompilerStrategy" do
+require_relative "spec_helper_initializer"
+
+describe "Shakapacker::CompilerStrategy" do
   describe "#from_config" do
     it "returns and instance of MtimeStrategy when compiler_strategy is set to mtime" do
-      allow(Webpacker.config).to receive(:compiler_strategy).and_return("mtime")
-      expect(Webpacker::CompilerStrategy.from_config).to be_an_instance_of(Webpacker::MtimeStrategy)
+      allow(Shakapacker.config).to receive(:compiler_strategy).and_return("mtime")
+      expect(Shakapacker::CompilerStrategy.from_config).to be_an_instance_of(Shakapacker::MtimeStrategy)
     end
 
     it "returns and instance of DigestStrategy when compiler_strategy is set to digest" do
-      allow(Webpacker.config).to receive(:compiler_strategy).and_return("digest")
-      expect(Webpacker::CompilerStrategy.from_config).to be_an_instance_of(Webpacker::DigestStrategy)
+      allow(Shakapacker.config).to receive(:compiler_strategy).and_return("digest")
+      expect(Shakapacker::CompilerStrategy.from_config).to be_an_instance_of(Shakapacker::DigestStrategy)
     end
 
     it "raise exception for unknown compiler_strategy in the config file" do
       expected_error_message = "Unknown strategy 'other'. Available options are 'mtime' and 'digest'."
-      allow(Webpacker.config).to receive(:compiler_strategy).and_return("other")
+      allow(Shakapacker.config).to receive(:compiler_strategy).and_return("other")
 
-      expect { Webpacker::CompilerStrategy.from_config }.to raise_error(expected_error_message)
+      expect { Shakapacker::CompilerStrategy.from_config }.to raise_error(expected_error_message)
     end
   end
 end
diff --git a/spec/configuration_spec.rb b/spec/configuration_spec.rb
index 2fca941f1..174019433 100644
--- a/spec/configuration_spec.rb
+++ b/spec/configuration_spec.rb
@@ -1,11 +1,13 @@
-describe "Webpacker::Configuration" do
+require_relative "spec_helper_initializer"
+
+describe "Shakapacker::Configuration" do
   ROOT_PATH = Pathname.new(File.expand_path("test_app", __dir__))
 
-  context "with standard webpacker.yml" do
+  context "with standard shakapacker.yml" do
     let(:config) do
-      Webpacker::Configuration.new(
+      Shakapacker::Configuration.new(
         root_path: ROOT_PATH,
-        config_path: Pathname.new(File.expand_path("./test_app/config/webpacker.yml", __dir__)),
+        config_path: Pathname.new(File.expand_path("./test_app/config/shakapacker.yml", __dir__)),
         env: "production"
       )
     end
@@ -41,7 +43,7 @@
     end
 
     it "#cache_path returns correct path" do
-      cache_path = File.expand_path File.join(File.dirname(__FILE__), "test_app/tmp/webpacker").to_s
+      cache_path = File.expand_path File.join(File.dirname(__FILE__), "test_app/tmp/shakapacker").to_s
       expect(config.cache_path.to_s).to eq cache_path
     end
 
@@ -56,13 +58,13 @@
 
       it "returns false in developemnt environemnt" do
         with_rails_env("development") do
-          expect(Webpacker.config.cache_manifest?).to be false
+          expect(Shakapacker.config.cache_manifest?).to be false
         end
       end
 
       it "returns false in test environment" do
         with_rails_env("test") do
-          expect(Webpacker.config.cache_manifest?).to be false
+          expect(Shakapacker.config.cache_manifest?).to be false
         end
       end
     end
@@ -74,13 +76,13 @@
 
       it "returns true in developemnt environemnt" do
         with_rails_env("development") do
-          expect(Webpacker.config.compile?).to be true
+          expect(Shakapacker.config.compile?).to be true
         end
       end
 
       it "returns true in test environemnt" do
         with_rails_env("test") do
-          expect(Webpacker.config.compile?).to be true
+          expect(Shakapacker.config.compile?).to be true
         end
       end
     end
@@ -92,13 +94,13 @@
 
       it "returns false in development environment" do
         with_rails_env("development") do
-          expect(Webpacker.config.nested_entries?).to be false
+          expect(Shakapacker.config.nested_entries?).to be false
         end
       end
 
       it "returns false in test environment" do
         with_rails_env("test") do
-          expect(Webpacker.config.nested_entries?).to be false
+          expect(Shakapacker.config.nested_entries?).to be false
         end
       end
     end
@@ -110,74 +112,74 @@
 
       it "returns true in development environment" do
         with_rails_env("development") do
-          expect(Webpacker.config.ensure_consistent_versioning?).to be true
+          expect(Shakapacker.config.ensure_consistent_versioning?).to be true
         end
       end
 
       it "returns false in test environment" do
         with_rails_env("test") do
-          expect(Webpacker.config.ensure_consistent_versioning?).to be false
+          expect(Shakapacker.config.ensure_consistent_versioning?).to be false
         end
       end
     end
 
-    describe "#webpacker_precompile?" do
+    describe "#shakapacker_precompile?" do
       before :each do
-        ENV["WEBPACKER_PRECOMPILE"] = nil
+        ENV["SHAKAPACKER_PRECOMPILE"] = nil
       end
 
-      subject { config.webpacker_precompile? }
+      subject { config.shakapacker_precompile? }
 
-      it "returns true when WEBPACKER_PRECOMPILE is unset" do
+      it "returns true when SHAKAPACKER_PRECOMPILE is unset" do
         is_expected.to be true
       end
 
-      it "returns false when WEBPACKER_PRECOMPILE sets to no" do
-        ENV["WEBPACKER_PRECOMPILE"] = "no"
+      it "returns false when SHAKAPACKER_PRECOMPILE sets to no" do
+        ENV["SHAKAPACKER_PRECOMPILE"] = "no"
         is_expected.to be false
       end
 
-      it "returns true when WEBPACKER_PRECOMPILE sets to yes" do
-        ENV["WEBPACKER_PRECOMPILE"] = "yes"
+      it "returns true when SHAKAPACKER_PRECOMPILE sets to yes" do
+        ENV["SHAKAPACKER_PRECOMPILE"] = "yes"
         is_expected.to be true
       end
 
-      it "returns false when WEBPACKER_PRECOMPILE sets to false" do
-        ENV["WEBPACKER_PRECOMPILE"] = "false"
+      it "returns false when SHAKAPACKER_PRECOMPILE sets to false" do
+        ENV["SHAKAPACKER_PRECOMPILE"] = "false"
         is_expected.to be false
       end
 
-      it "returns true when WEBPACKER_PRECOMPILE sets to true" do
-        ENV["WEBPACKER_PRECOMPILE"] = "true"
+      it "returns true when SHAKAPACKER_PRECOMPILE sets to true" do
+        ENV["SHAKAPACKER_PRECOMPILE"] = "true"
         is_expected.to be true
       end
 
-      it "returns false when WEBPACKER_PRECOMPILE sets to n" do
-        ENV["WEBPACKER_PRECOMPILE"] = "n"
+      it "returns false when SHAKAPACKER_PRECOMPILE sets to n" do
+        ENV["SHAKAPACKER_PRECOMPILE"] = "n"
         is_expected.to be false
       end
 
-      it "returns true when WEBPACKER_PRECOMPILE sets to y" do
-        ENV["WEBPACKER_PRECOMPILE"] = "y"
+      it "returns true when SHAKAPACKER_PRECOMPILE sets to y" do
+        ENV["SHAKAPACKER_PRECOMPILE"] = "y"
         is_expected.to be true
       end
 
-      it "returns false when WEBPACKER_PRECOMPILE sets to f" do
-        ENV["WEBPACKER_PRECOMPILE"] = "f"
+      it "returns false when SHAKAPACKER_PRECOMPILE sets to f" do
+        ENV["SHAKAPACKER_PRECOMPILE"] = "f"
         is_expected.to be false
       end
 
-      it "returns true when WEBPACKER_PRECOMPILE sets to t" do
-        ENV["WEBPACKER_PRECOMPILE"] = "t"
+      it "returns true when SHAKAPACKER_PRECOMPILE sets to t" do
+        ENV["SHAKAPACKER_PRECOMPILE"] = "t"
         is_expected.to be true
       end
     end
   end
 
-  context "with webpacker config file containing public_output_path entry" do
-    config = Webpacker::Configuration.new(
+  context "with shakapacker config file containing public_output_path entry" do
+    config = Shakapacker::Configuration.new(
       root_path: ROOT_PATH,
-      config_path: Pathname.new(File.expand_path("./test_app/config/webpacker_public_root.yml", __dir__)),
+      config_path: Pathname.new(File.expand_path("./test_app/config/shakapacker_public_root.yml", __dir__)),
       env: "production"
     )
 
@@ -187,10 +189,10 @@
     end
   end
 
-  context "with webpacker config file containing manifext_path entry" do
-    config = Webpacker::Configuration.new(
+  context "with shakapacker config file containing manifext_path entry" do
+    config = Shakapacker::Configuration.new(
       root_path: ROOT_PATH,
-      config_path: Pathname.new(File.expand_path("./test_app/config/webpacker_manifest_path.yml", __dir__)),
+      config_path: Pathname.new(File.expand_path("./test_app/config/shakapacker_manifest_path.yml", __dir__)),
       env: "production"
     )
 
@@ -200,55 +202,55 @@
     end
   end
 
-  context "with webpacker_precompile entry set to false" do
-    describe "#webpacker_precompile?" do
+  context "with shakapacker_precompile entry set to false" do
+    describe "#shakapacker_precompile?" do
       before :each do
-        ENV["WEBPACKER_PRECOMPILE"] = nil
+        ENV["SHAKAPACKER_PRECOMPILE"] = nil
       end
 
       let(:config) {
-        Webpacker::Configuration.new(
+        Shakapacker::Configuration.new(
           root_path: ROOT_PATH,
-          config_path: Pathname.new(File.expand_path("./test_app/config/webpacker_no_precompile.yml", __dir__)),
+          config_path: Pathname.new(File.expand_path("./test_app/config/shakapacker_no_precompile.yml", __dir__)),
           env: "production"
         )
       }
 
-      subject { config.webpacker_precompile? }
+      subject { config.shakapacker_precompile? }
 
-      it "returns false with unset WEBPACKER_PRECOMPILE" do
+      it "returns false with unset SHAKAPACKER_PRECOMPILE" do
         expect(subject).to be false
       end
 
-      it "returns true with WEBPACKER_PRECOMPILE set to true" do
-        ENV["WEBPACKER_PRECOMPILE"] = "true"
+      it "returns true with SHAKAPACKER_PRECOMPILE set to true" do
+        ENV["SHAKAPACKER_PRECOMPILE"] = "true"
         expect(subject).to be true
       end
 
-      it "returns false with WEBPACKER_PRECOMPILE set to nil" do
-        ENV["WEBPACKER_PRECOMPILE"] = nil
+      it "returns false with SHAKAPACKER_PRECOMPILE set to nil" do
+        ENV["SHAKAPACKER_PRECOMPILE"] = nil
         expect(subject).to be false
       end
     end
   end
 
-  context "with webpacker config file containing invalid path" do
-    config = Webpacker::Configuration.new(
+  context "with shakapacker config file containing invalid path" do
+    config = Shakapacker::Configuration.new(
       root_path: ROOT_PATH,
       config_path: Pathname.new(File.expand_path("./test_app/config/invalid_path.yml", __dir__)),
       env: "default"
     )
 
-    it "#webpacker_precompile? returns false" do
-      expect(config.webpacker_precompile?).to be false
+    it "#shakapacker_precompile? returns false" do
+      expect(config.shakapacker_precompile?).to be false
     end
   end
 
-  context "with webpacker config file with defaults fallback" do
+  context "with shakapacker config file with defaults fallback" do
     let(:config) do
-      Webpacker::Configuration.new(
+      Shakapacker::Configuration.new(
         root_path: ROOT_PATH,
-        config_path: Pathname.new(File.expand_path("./test_app/config/webpacker_defaults_fallback.yml", __dir__)),
+        config_path: Pathname.new(File.expand_path("./test_app/config/shakapacker_defaults_fallback.yml", __dir__)),
         env: "default"
       )
     end
@@ -257,16 +259,16 @@
       expect(config.cache_manifest?).to be false
     end
 
-    it "#webpacker_precompile? uses 'default' config from custom file" do
-      expect(config.webpacker_precompile?).to be false
+    it "#shakapacker_precompile? uses 'default' config from custom file" do
+      expect(config.shakapacker_precompile?).to be false
     end
   end
 
   context "falls back to bundled production config for custom environments" do
     let(:config) do
-      Webpacker::Configuration.new(
+      Shakapacker::Configuration.new(
         root_path: ROOT_PATH,
-        config_path: Pathname.new(File.expand_path("./test_app/config/webpacker_defaults_fallback.yml", __dir__)),
+        config_path: Pathname.new(File.expand_path("./test_app/config/shakapacker_defaults_fallback.yml", __dir__)),
         env: "staging"
       )
     end
@@ -274,8 +276,48 @@
     it "#cache_manifest? fall back to 'production' config from bundled file" do
       expect(config.cache_manifest?).to be true
     end
-    it "#webpacker_precompile? use 'staging' config from custom file" do
-      expect(config.webpacker_precompile?).to be false
+    it "#shakapacker_precompile? use 'staging' config from custom file" do
+      expect(config.shakapacker_precompile?).to be false
+    end
+  end
+
+  context "#source_entry_path" do
+    let(:config) do
+      Shakapacker::Configuration.new(
+        root_path: ROOT_PATH,
+        config_path: Pathname.new(File.expand_path("./test_app/config/shakapacker.yml", __dir__)),
+        env: "production"
+      )
+    end
+
+    it "returns correct path with source_entry_path starting with 'extra_path'" do
+      allow(config).to receive(:fetch).with(:source_path).and_return("the_source_path")
+      allow(config).to receive(:fetch).with(:source_entry_path).and_return("extra_path")
+
+      actual = config.source_entry_path.to_s
+      expected = "#{config.source_path.to_s}/extra_path"
+
+      expect(actual).to eq(expected)
+    end
+
+    it "returns correct path with source_entry_path starting with /" do
+      allow(config).to receive(:fetch).with(:source_path).and_return("the_source_path")
+      allow(config).to receive(:fetch).with(:source_entry_path).and_return("/")
+
+      actual = config.source_entry_path.to_s
+      expected = config.source_path.to_s
+
+      expect(actual).to eq(expected)
+    end
+
+    it "returns correct path with source_entry_path starting with /extra_path" do
+      allow(config).to receive(:fetch).with(:source_path).and_return("the_source_path")
+      allow(config).to receive(:fetch).with(:source_entry_path).and_return("/extra_path")
+
+      actual = config.source_entry_path.to_s
+      expected = "#{config.source_path.to_s}/extra_path"
+
+      expect(actual).to eq(expected)
     end
   end
 end
diff --git a/spec/dev_server_runner_spec.rb b/spec/dev_server_runner_spec.rb
index 147cc0a70..abf2be819 100644
--- a/spec/dev_server_runner_spec.rb
+++ b/spec/dev_server_runner_spec.rb
@@ -1,16 +1,17 @@
-require "webpacker/dev_server_runner"
+require_relative "spec_helper_initializer"
+require "shakapacker/dev_server_runner"
 
 describe "DevServerRunner" do
   before do
     @original_node_env, ENV["NODE_ENV"] = ENV["NODE_ENV"], "development"
     @original_rails_env, ENV["RAILS_ENV"] = ENV["RAILS_ENV"], "development"
-    @original_webpacker_config = ENV["WEBPACKER_CONFIG"]
+    @original_shakapacker_config = ENV["SHAKAPACKER_CONFIG"]
   end
 
   after do
     ENV["NODE_ENV"] = @original_node_env
     ENV["RAILS_ENV"] = @original_rails_env
-    ENV["WEBPACKER_CONFIG"] = @original_webpacker_config
+    ENV["SHAKAPACKER_CONFIG"] = @original_shakapacker_config
   end
 
   let(:test_app_path) { File.expand_path("test_app", __dir__) }
@@ -37,24 +38,24 @@
     allow(dev_server).to receive(:https?).and_return(true)
     allow(dev_server).to receive(:hmr?).and_return(false)
 
-    allow(Webpacker::DevServer).to receive(:new) do
+    allow(Shakapacker::DevServer).to receive(:new) do
       verify_command(cmd, argv: (["--https"]))
     end.and_return(dev_server)
   end
   it "accepts environment variables" do
     cmd = ["#{test_app_path}/node_modules/.bin/webpack", "serve", "--config", "#{test_app_path}/config/webpack/webpack.config.js"]
-    env = Webpacker::Compiler.env.dup
-    ENV["WEBPACKER_CONFIG"] = env["WEBPACKER_CONFIG"] = "#{test_app_path}/config/webpacker_other_location.yml"
+    env = Shakapacker::Compiler.env.dup
+    ENV["SHAKAPACKER_CONFIG"] = env["SHAKAPACKER_CONFIG"] = "#{test_app_path}/config/shakapacker_other_location.yml"
     env["WEBPACK_SERVE"] = "true"
     verify_command(cmd, env: env)
   end
 
   private
 
-    def verify_command(cmd, use_node_modules: true, argv: [], env: Webpacker::Compiler.env)
+    def verify_command(cmd, use_node_modules: true, argv: [], env: Shakapacker::Compiler.env)
       cwd = Dir.pwd
       Dir.chdir(test_app_path)
-      klass = Webpacker::DevServerRunner
+      klass = Shakapacker::DevServerRunner
       instance = klass.new(argv)
 
       allow(klass).to receive(:new).and_return(instance)
diff --git a/spec/dev_server_spec.rb b/spec/dev_server_spec.rb
index d7b7cc015..275ed506b 100644
--- a/spec/dev_server_spec.rb
+++ b/spec/dev_server_spec.rb
@@ -1,45 +1,133 @@
+require_relative "spec_helper_initializer"
+
 describe "DevServer" do
   it "doesn't run by default" do
-    expect(Webpacker.dev_server.running?).to be_falsy
+    expect(Shakapacker.dev_server.running?).to be_falsy
   end
 
   it "uses localhost as host in development environment" do
     with_rails_env("development") do
-      expect(Webpacker.dev_server.host).to eq "localhost"
+      expect(Shakapacker.dev_server.host).to eq "localhost"
     end
   end
 
   it "uses port 3035 in development environment" do
     with_rails_env("development") do
-      expect(Webpacker.dev_server.port).to eq 3035
+      expect(Shakapacker.dev_server.port).to eq 3035
     end
   end
 
   it "doesn't use https in development environment" do
     with_rails_env("development") do
-      expect(Webpacker.dev_server.https?).to be false
+      expect(Shakapacker.dev_server.https?).to be false
     end
   end
 
   it "uses http protocol in development environment" do
     with_rails_env("development") do
-      expect(Webpacker.dev_server.protocol).to eq "http"
+      expect(Shakapacker.dev_server.protocol).to eq "http"
     end
   end
 
   it "sets host_with_port to localhost:3035 in development environment" do
     with_rails_env("development") do
-      expect(Webpacker.dev_server.host_with_port).to eq "localhost:3035"
+      expect(Shakapacker.dev_server.host_with_port).to eq "localhost:3035"
     end
   end
 
   it "doesn't use pretty in development environment" do
     with_rails_env("development") do
-      expect(Webpacker.dev_server.pretty?).to be false
+      expect(Shakapacker.dev_server.pretty?).to be false
+    end
+  end
+
+  it "users SHAKAPACKER_DEV_SERVER for DEFAULT_ENV_PREFIX" do
+    expect(Shakapacker::DevServer::DEFAULT_ENV_PREFIX).to eq "SHAKAPACKER_DEV_SERVER"
+  end
+
+  context "#protocol in development environment" do
+    let(:dev_server) { Shakapacker.dev_server }
+
+    it "returns `http` by default (with unset `server` and `https`)" do
+      with_rails_env("development") do
+        expect(dev_server.protocol).to eq "http"
+      end
+    end
+
+    it "returns `https` when `server` is set to `https`" do
+      expect(dev_server).to receive(:server).and_return("https")
+
+      with_rails_env("development") do
+        expect(dev_server.protocol).to eq "https"
+      end
+    end
+
+    it "returns `https` with unset `server` and `https` set to `true`" do
+      expect(dev_server).to receive(:server).and_return("http")
+      expect(dev_server).to receive(:https?).and_return(true)
+
+      with_rails_env("development") do
+        expect(dev_server.protocol).to eq "https"
+      end
     end
   end
 
-  it "users WEBPACKER_DEV_SERVER for DEFAULT_ENV_PREFIX" do
-    expect(Webpacker::DevServer::DEFAULT_ENV_PREFIX).to eq "WEBPACKER_DEV_SERVER"
+  context "#server in development environment" do
+    let(:dev_server) { Shakapacker.dev_server }
+
+    it "returns `http` when unset" do
+      expect(dev_server).to receive(:fetch).with(:server).and_return(nil)
+
+      with_rails_env("development") do
+        expect(dev_server.server).to eq "http"
+      end
+    end
+
+    it "returns `http` when set to `https`" do
+      expect(dev_server).to receive(:fetch).with(:server).and_return("http")
+
+      with_rails_env("development") do
+        expect(dev_server.server).to eq "http"
+      end
+    end
+
+    it "returns `http` when set to a hash with `type: http`" do
+      expect(dev_server).to receive(:fetch).with(:server).and_return({
+        type: "http",
+        options: {}
+      })
+
+      with_rails_env("development") do
+        expect(dev_server.server).to eq "http"
+      end
+    end
+
+    it "returns `https` when set to `https`" do
+      expect(dev_server).to receive(:fetch).with(:server).and_return("https")
+
+      with_rails_env("development") do
+        expect(dev_server.server).to eq "https"
+      end
+    end
+
+    it "returns `https` when set to a hash with `type: https`" do
+      expect(dev_server).to receive(:fetch).with(:server).and_return({
+        type: "https",
+        options: {}
+      })
+
+      with_rails_env("development") do
+        expect(dev_server.server).to eq "https"
+      end
+    end
+
+    it "returns `http` when set to any value except `http` and `https`" do
+      expect(dev_server).to receive(:fetch).twice.with(:server).and_return("other-than-https")
+
+      with_rails_env("development") do
+        expect(dev_server.server).to eq "http"
+        expect { dev_server.server }.to output(/WARNING/).to_stdout
+      end
+    end
   end
 end
diff --git a/spec/digest_strategy_spec.rb b/spec/digest_strategy_spec.rb
index 4eed15676..f967be917 100644
--- a/spec/digest_strategy_spec.rb
+++ b/spec/digest_strategy_spec.rb
@@ -1,3 +1,5 @@
+require_relative "spec_helper_initializer"
+
 describe "DigestStrategy" do
   def remove_compilation_digest_path
     @digest_strategy.send(:compilation_digest_path).tap do |path|
@@ -6,7 +8,7 @@ def remove_compilation_digest_path
   end
 
   before :all do
-    @digest_strategy = Webpacker::DigestStrategy.new
+    @digest_strategy = Shakapacker::DigestStrategy.new
     remove_compilation_digest_path
   end
 
@@ -27,7 +29,7 @@ def remove_compilation_digest_path
 
   it "generates correct compilation_digest_path" do
     actual_path = @digest_strategy.send(:compilation_digest_path).basename.to_s
-    expected_path = "last-compilation-digest-#{Webpacker.env}"
+    expected_path = "last-compilation-digest-#{Shakapacker.env}"
     expect(actual_path).to eq expected_path
   end
 end
diff --git a/spec/engine_rake_tasks_spec.rb b/spec/engine_rake_tasks_spec.rb
index fd07fe12e..ea6a23823 100644
--- a/spec/engine_rake_tasks_spec.rb
+++ b/spec/engine_rake_tasks_spec.rb
@@ -1,3 +1,5 @@
+require_relative "spec_helper_initializer"
+
 describe "EngineRakeTasks" do
   before :context do
     remove_webpack_binstubs
@@ -7,19 +9,14 @@
     remove_webpack_binstubs
   end
 
-  it "mounts app:webpacker task successfully" do
+  it "mounts app:shakapacker task successfully" do
     output = Dir.chdir(mounted_app_path) { `rake -T` }
-    expect(output).to include "app:webpacker"
+    expect(output).to include "app:shakapacker"
   end
 
   it "binstubs adds only expected files to bin directory" do
-    original_files_in_bin = current_files_in_bin
-
-    Dir.chdir(mounted_app_path) { `bundle exec rake app:webpacker:binstubs` }
-    webpack_binstub_paths.each { |path| expect(File.exist?(path)).to be true }
-
-    # and no other files are added
-    expect(current_files_in_bin - webpack_binstub_paths).to match_array original_files_in_bin
+    Dir.chdir(mounted_app_path) { `bundle exec rake app:shakapacker:binstubs` }
+    expected_binstub_paths.each { |path| expect(File.exist?(path)).to be true }
   end
 
   private
@@ -31,16 +28,15 @@ def current_files_in_bin
       Dir.glob("#{mounted_app_path}/test/dummy/bin/*")
     end
 
-    def webpack_binstub_paths
-      [
-        "#{mounted_app_path}/test/dummy/bin/yarn",
-        "#{mounted_app_path}/test/dummy/bin/webpacker",
-        "#{mounted_app_path}/test/dummy/bin/webpacker-dev-server",
-      ]
+    def expected_binstub_paths
+      gem_path = File.expand_path("..", __dir__)
+      Dir.chdir("#{gem_path}/lib/install/bin") do
+        Dir.glob("*").map { |file| "#{mounted_app_path}/test/dummy/bin/#{file}" }
+      end
     end
 
     def remove_webpack_binstubs
-      webpack_binstub_paths.each do |path|
+      expected_binstub_paths.each do |path|
         File.delete(path) if File.exist?(path)
       end
     end
diff --git a/spec/env_spec.rb b/spec/env_spec.rb
index 196e17277..2527c718a 100644
--- a/spec/env_spec.rb
+++ b/spec/env_spec.rb
@@ -1,21 +1,23 @@
+require_relative "spec_helper_initializer"
+
 RSpec.describe "Env" do
-  it "uses the same env for Rails and Webpacker" do
-    expect(Webpacker.env).to eq Rails.env
+  it "uses the same env for Rails and Shakapacker" do
+    expect(Shakapacker.env).to eq Rails.env
   end
 
   it "uses production env without config" do
     with_rails_env("foo") do
-      expect(Webpacker.env).to eq "production"
+      expect(Shakapacker.env).to eq "production"
     end
   end
 
   it "uses the given env in custom config" do
     with_rails_env("staging") do
-      expect(Webpacker.env).to eq "staging"
+      expect(Shakapacker.env).to eq "staging"
     end
   end
 
   it "uses 'production' as default env" do
-    expect(Webpacker::DEFAULT_ENV).to eq "production"
+    expect(Shakapacker::DEFAULT_ENV).to eq "production"
   end
 end
diff --git a/spec/helper_spec.rb b/spec/helper_spec.rb
index 0427849bc..5dd9c4b51 100644
--- a/spec/helper_spec.rb
+++ b/spec/helper_spec.rb
@@ -1,12 +1,14 @@
+require_relative "spec_helper_initializer"
+
 module ActionView::TestCase::Behavior
   attr_accessor :request
 
-  describe "Webpacker::Helper" do
+  describe "Shakapacker::Helper" do
     let(:application_stylesheet_chunks) { %w[/packs/1-c20632e7baf2c81200d3.chunk.css /packs/application-k344a6d59eef8632c9d1.chunk.css] }
     let(:hello_stimulus_stylesheet_chunks) { %w[/packs/1-c20632e7baf2c81200d3.chunk.css /packs/hello_stimulus-k344a6d59eef8632c9d1.chunk.css] }
 
     before :each do
-      extend Webpacker::Helper
+      extend Shakapacker::Helper
       extend ActionView::Helpers
       extend ActionView::Helpers::AssetTagHelper
       extend ActionView::TestCase::Behavior
diff --git a/spec/instance_spec.rb b/spec/instance_spec.rb
new file mode 100644
index 000000000..9d9667ec5
--- /dev/null
+++ b/spec/instance_spec.rb
@@ -0,0 +1,31 @@
+require_relative "spec_helper_initializer"
+
+describe "Shakapacker::Instance" do
+  before :each do
+    ENV.delete("WEBPACKER_CONFIG")
+    ENV.delete("SHAKAPACKER_CONFIG")
+    Shakapacker.instance = Shakapacker::Instance.new
+  end
+
+  after :each do
+    ENV.delete("WEBPACKER_CONFIG")
+    ENV.delete("SHAKAPACKER_CONFIG")
+    Shakapacker.instance = Shakapacker::Instance.new
+  end
+
+  it "uses default config path if no env variable defined" do
+    actual_config_path = Rails.root.join("config/shakapacker.yml")
+    expected_config_path = Shakapacker.config.config_path
+
+    expect(expected_config_path).to eq(actual_config_path)
+  end
+
+  it "uses SHAKAPACKER_CONFIG env variable for config file" do
+    ENV["SHAKAPACKER_CONFIG"] = "/some/random/path.yml"
+
+    actual_config_path = "/some/random/path.yml"
+    expected_config_path = Shakapacker.config.config_path.to_s
+
+    expect(expected_config_path).to eq(actual_config_path)
+  end
+end
diff --git a/spec/manifest_spec.rb b/spec/manifest_spec.rb
index 7a49c255a..53e0f4a97 100644
--- a/spec/manifest_spec.rb
+++ b/spec/manifest_spec.rb
@@ -1,73 +1,75 @@
-describe "Webpacker::Manifest" do
+require_relative "spec_helper_initializer"
+
+describe "Shakapacker::Manifest" do
   let(:manifest_path) { File.expand_path File.join(File.dirname(__FILE__), "test_app/public/packs", "manifest.json").to_s }
 
   it "#lookup! throws exception for a non-existing asset file" do
     asset_file = "calendar.js"
     expected_error_message = "Shakapacker can't find #{asset_file} in #{manifest_path}"
 
-    allow(Webpacker.config).to receive(:compile?).and_return(false)
+    allow(Shakapacker.config).to receive(:compile?).and_return(false)
 
     expect {
-      Webpacker.manifest.lookup!(asset_file)
-    }.to raise_error(Webpacker::Manifest::MissingEntryError, /#{expected_error_message}/)
+      Shakapacker.manifest.lookup!(asset_file)
+    }.to raise_error(Shakapacker::Manifest::MissingEntryError, /#{expected_error_message}/)
   end
 
   it "#lookup! throws exception for a non-existing asset file with type and without extension" do
     asset_file = "calendar"
     expected_error_message = "Shakapacker can't find #{asset_file}.js in #{manifest_path}"
 
-    allow(Webpacker.config).to receive(:compile?).and_return(false)
+    allow(Shakapacker.config).to receive(:compile?).and_return(false)
 
     expect {
-      Webpacker.manifest.lookup!(asset_file, type: :javascript)
-    }.to raise_error(Webpacker::Manifest::MissingEntryError, /#{expected_error_message}/)
+      Shakapacker.manifest.lookup!(asset_file, type: :javascript)
+    }.to raise_error(Shakapacker::Manifest::MissingEntryError, /#{expected_error_message}/)
   end
 
   it "#lookup! returns path to bundled bootstrap.js" do
-    actual = Webpacker.manifest.lookup!("bootstrap.js")
+    actual = Shakapacker.manifest.lookup!("bootstrap.js")
     expected = "/packs/bootstrap-300631c4f0e0f9c865bc.js"
 
     expect(actual).to eq expected
   end
 
   it "#lookup_pack_with_chunks! returns array of path to bundled bootstrap with type of javascript" do
-    actual = Webpacker.manifest.lookup_pack_with_chunks!("bootstrap", type: :javascript)
+    actual = Shakapacker.manifest.lookup_pack_with_chunks!("bootstrap", type: :javascript)
     expected = ["/packs/bootstrap-300631c4f0e0f9c865bc.js"]
 
     expect(actual).to eq expected
   end
 
   it "#lookup_with_chunks! returns array of path to bundled bootstrap.js with type of javascript" do
-    actual = Webpacker.manifest.lookup_pack_with_chunks!("bootstrap.js", type: :javascript)
+    actual = Shakapacker.manifest.lookup_pack_with_chunks!("bootstrap.js", type: :javascript)
     expected = ["/packs/bootstrap-300631c4f0e0f9c865bc.js"]
 
     expect(actual).to eq expected
   end
 
   it "#lookup_with_chunks! returns array of path to bundled 'print/application' without extension and in a sub-directory" do
-    actual = Webpacker.manifest.lookup_pack_with_chunks!("print/application", type: :css)
+    actual = Shakapacker.manifest.lookup_pack_with_chunks!("print/application", type: :css)
     expected = ["/packs/print/application-983b6c164a47f7ed49cd.css"]
 
     expect(actual).to eq expected
   end
 
   it "#lookup_with_chunks! returns array of path to bundled 'print/application.css' in a sub-directory" do
-    actual = Webpacker.manifest.lookup_pack_with_chunks!("print/application.css", type: :css)
+    actual = Shakapacker.manifest.lookup_pack_with_chunks!("print/application.css", type: :css)
     expected = ["/packs/print/application-983b6c164a47f7ed49cd.css"]
 
     expect(actual).to eq expected
   end
 
   it "#lookup returns nil for non-existing asset file" do
-    expect(Webpacker.manifest.lookup("foo.js")).to be nil
+    expect(Shakapacker.manifest.lookup("foo.js")).to be nil
   end
 
   it "#lookup_pack_with_chunks returns nil for non-existing asset file" do
-    expect(Webpacker.manifest.lookup_pack_with_chunks("foo.js")).to be nil
+    expect(Shakapacker.manifest.lookup_pack_with_chunks("foo.js")).to be nil
   end
 
   it "#lookup returns path for bootstrap.js" do
-    actual = Webpacker.manifest.lookup("bootstrap.js")
+    actual = Shakapacker.manifest.lookup("bootstrap.js")
     expected = "/packs/bootstrap-300631c4f0e0f9c865bc.js"
 
     expect(actual).to eq expected
@@ -78,15 +80,15 @@
 
     expected_error_message = "Shakapacker can't find #{asset_file}.js in #{manifest_path}"
 
-    allow(Webpacker.config).to receive(:compile?).and_return(false)
+    allow(Shakapacker.config).to receive(:compile?).and_return(false)
 
     expect {
-      Webpacker.manifest.lookup_pack_with_chunks!(asset_file, type: :javascript)
-    }.to raise_error(Webpacker::Manifest::MissingEntryError, /#{expected_error_message}/)
+      Shakapacker.manifest.lookup_pack_with_chunks!(asset_file, type: :javascript)
+    }.to raise_error(Shakapacker::Manifest::MissingEntryError, /#{expected_error_message}/)
   end
 
   it "#lookup_pack_with_chunks! returns array of paths to bundled js files with 'application' in their name" do
-    actual_application_entrypoints = Webpacker.manifest.lookup_pack_with_chunks!("application", type: :javascript)
+    actual_application_entrypoints = Shakapacker.manifest.lookup_pack_with_chunks!("application", type: :javascript)
     expected_application_entrypoints = [
       "/packs/vendors~application~bootstrap-c20632e7baf2c81200d3.chunk.js",
       "/packs/vendors~application-e55f2aae30c07fb6d82a.chunk.js",
diff --git a/spec/mounted_app/test/dummy/config/application.rb b/spec/mounted_app/test/dummy/config/application.rb
index 24f516874..23c9c9a75 100644
--- a/spec/mounted_app/test/dummy/config/application.rb
+++ b/spec/mounted_app/test/dummy/config/application.rb
@@ -1,6 +1,6 @@
 require "action_controller/railtie"
 require "action_view/railtie"
-require "webpacker"
+require "shakapacker"
 
 module TestDummyApp
   class Application < Rails::Application
diff --git a/spec/mounted_app/test/dummy/config/webpacker.yml b/spec/mounted_app/test/dummy/config/webpacker.yml
index 22705f410..4de9764cb 100644
--- a/spec/mounted_app/test/dummy/config/webpacker.yml
+++ b/spec/mounted_app/test/dummy/config/webpacker.yml
@@ -1,10 +1,10 @@
-# Note: You must restart bin/webpacker-dev-server for changes to take effect
+# Note: You must restart bin/shakapacker-dev-server for changes to take effect
 
 default: &default
   source_path: app/javascript
   source_entry_path: entrypoints
   public_output_path: packs
-  cache_path: tmp/webpacker
+  cache_path: tmp/shakapacker
   webpack_loader: babel
 
   # Additional paths webpack should look up modules
diff --git a/spec/mtime_strategy_spec.rb b/spec/mtime_strategy_spec.rb
index 7abdde327..631ddc381 100644
--- a/spec/mtime_strategy_spec.rb
+++ b/spec/mtime_strategy_spec.rb
@@ -1,5 +1,7 @@
-describe "Webpacker::MtimeStrategy" do
-  let(:mtime_strategy) { Webpacker::MtimeStrategy.new }
+require_relative "spec_helper_initializer"
+
+describe "Shakapacker::MtimeStrategy" do
+  let(:mtime_strategy) { Shakapacker::MtimeStrategy.new }
   let(:manifest_timestamp) { Time.parse("2021-01-01 12:34:56 UTC") }
 
   describe "#fresh?" do
diff --git a/spec/rake_tasks_spec.rb b/spec/rake_tasks_spec.rb
index 58d0f5c9f..795bf9a47 100644
--- a/spec/rake_tasks_spec.rb
+++ b/spec/rake_tasks_spec.rb
@@ -1,32 +1,34 @@
+require_relative "spec_helper_initializer"
+
 describe "RakeTasks" do
   let(:test_app_path) { File.expand_path("test_app", __dir__) }
 
-  it "`rake -T` lists webpacker tasks" do
+  it "`rake -T` lists Shakapacker tasks" do
     output = Dir.chdir(test_app_path) { `rake -T` }
-    expect(output).to include "webpacker"
-    expect(output).to include "webpacker:check_binstubs"
-    expect(output).to include "webpacker:check_node"
-    expect(output).to include "webpacker:check_yarn"
-    expect(output).to include "webpacker:clean"
-    expect(output).to include "webpacker:clobber"
-    expect(output).to include "webpacker:compile"
-    expect(output).to include "webpacker:install"
-    expect(output).to include "webpacker:verify_install"
+    expect(output).to include "shakapacker"
+    expect(output).to include "shakapacker:check_binstubs"
+    expect(output).to include "shakapacker:check_node"
+    expect(output).to include "shakapacker:check_yarn"
+    expect(output).to include "shakapacker:clean"
+    expect(output).to include "shakapacker:clobber"
+    expect(output).to include "shakapacker:compile"
+    expect(output).to include "shakapacker:install"
+    expect(output).to include "shakapacker:verify_install"
   end
 
-  it "`webpacker:check_binstubs` doesn't get 'webpack binstub not found' error" do
-    output = Dir.chdir(test_app_path) { `rake webpacker:check_binstubs 2>&1` }
+  it "`shakapacker:check_binstubs` doesn't get 'webpack binstub not found' error" do
+    output = Dir.chdir(test_app_path) { `rake shakapacker:check_binstubs 2>&1` }
     expect(output).to_not include "webpack binstub not found."
   end
 
-  it "`webpacker:check_node` doesn't get 'Webpacker requires Node.js' error" do
-    output = Dir.chdir(test_app_path) { `rake webpacker:check_node 2>&1` }
-    expect(output).to_not include "Webpacker requires Node.js"
+  it "`shakapacker:check_node` doesn't get 'shakapacker requires Node.js' error" do
+    output = Dir.chdir(test_app_path) { `rake shakapacker:check_node 2>&1` }
+    expect(output).to_not include "Shakapacker requires Node.js"
   end
 
-  it "`webpacker:check_yarn` doesn't get error related to yarn" do
-    output = Dir.chdir(test_app_path) { `rake webpacker:check_yarn 2>&1` }
+  it "`shakapacker:check_yarn` doesn't get error related to yarn" do
+    output = Dir.chdir(test_app_path) { `rake shakapacker:check_yarn 2>&1` }
     expect(output).to_not include "Yarn not installed"
-    expect(output).to_not include "Webpacker requires Yarn"
+    expect(output).to_not include "Shakapacker requires Yarn"
   end
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index f29a37876..5ae5b6962 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -96,28 +96,3 @@
   Kernel.srand config.seed
 =end
 end
-
-require_relative "test_app/config/environment"
-
-Rails.env = "production"
-
-Webpacker.instance = ::Webpacker::Instance.new
-
-def reloaded_config
-  Webpacker.instance.instance_variable_set(:@env, nil)
-  Webpacker.instance.instance_variable_set(:@config, nil)
-  Webpacker.instance.instance_variable_set(:@dev_server, nil)
-  Webpacker.env
-  Webpacker.config
-  Webpacker.dev_server
-end
-
-def with_rails_env(env)
-  original = Rails.env
-  Rails.env = ActiveSupport::StringInquirer.new(env)
-  reloaded_config
-  yield
-ensure
-  Rails.env = ActiveSupport::StringInquirer.new(original)
-  reloaded_config
-end
diff --git a/spec/spec_helper_initializer.rb b/spec/spec_helper_initializer.rb
new file mode 100644
index 000000000..b6ff7c3c9
--- /dev/null
+++ b/spec/spec_helper_initializer.rb
@@ -0,0 +1,24 @@
+require_relative "test_app/config/environment"
+
+Rails.env = "production"
+
+Shakapacker.instance = ::Shakapacker::Instance.new
+
+def reloaded_config
+  Shakapacker.instance.instance_variable_set(:@env, nil)
+  Shakapacker.instance.instance_variable_set(:@config, nil)
+  Shakapacker.instance.instance_variable_set(:@dev_server, nil)
+  Shakapacker.env
+  Shakapacker.config
+  Shakapacker.dev_server
+end
+
+def with_rails_env(env)
+  original = Rails.env
+  Rails.env = ActiveSupport::StringInquirer.new(env)
+  reloaded_config
+  yield
+ensure
+  Rails.env = ActiveSupport::StringInquirer.new(original)
+  reloaded_config
+end
diff --git a/spec/test_app/.gitignore b/spec/test_app/.gitignore
new file mode 100644
index 000000000..e8cd2e2fd
--- /dev/null
+++ b/spec/test_app/.gitignore
@@ -0,0 +1,2 @@
+log/
+tmp/
diff --git a/spec/test_app/app/javascript/entrypoints/application.js b/spec/test_app/app/javascript/entrypoints/application.js
index 54b106ee0..a2ecbca18 100644
--- a/spec/test_app/app/javascript/entrypoints/application.js
+++ b/spec/test_app/app/javascript/entrypoints/application.js
@@ -7,4 +7,4 @@
 // To reference this file, add <%= javascript_pack_tag 'application' %> to the appropriate
 // layout file, like app/views/layouts/application.html.erb
 
-console.log('Hello World from Webpacker')
+console.log('Hello World from shakapacker')
diff --git a/spec/test_app/bin/webpacker b/spec/test_app/bin/shakapacker
similarity index 70%
rename from spec/test_app/bin/webpacker
rename to spec/test_app/bin/shakapacker
index c9c03f735..0c2d3a1e4 100644
--- a/spec/test_app/bin/webpacker
+++ b/spec/test_app/bin/shakapacker
@@ -9,6 +9,6 @@ ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../../Gemfile",
 
 require "bundler/setup"
 
-require "webpacker"
-require "webpacker/webpack_runner"
-Webpacker::WebpackRunner.run(ARGV)
+require "shakapacker"
+require "shakapacker/webpack_runner"
+Shakapacker::WebpackRunner.run(ARGV)
diff --git a/spec/test_app/bin/webpacker-dev-server b/spec/test_app/bin/shakapacker-dev-server
similarity index 69%
rename from spec/test_app/bin/webpacker-dev-server
rename to spec/test_app/bin/shakapacker-dev-server
index 76c277ce0..b5d6fd31c 100755
--- a/spec/test_app/bin/webpacker-dev-server
+++ b/spec/test_app/bin/shakapacker-dev-server
@@ -9,6 +9,6 @@ ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../../Gemfile",
 
 require "bundler/setup"
 
-require "webpacker"
-require "webpacker/dev_server_runner"
-Webpacker::DevServerRunner.run(ARGV)
+require "shakapacker"
+require "shakapacker/dev_server_runner"
+Shakapacker::DevServerRunner.run(ARGV)
diff --git a/spec/test_app/config/application.rb b/spec/test_app/config/application.rb
index 246f3c2ff..12a11ac35 100644
--- a/spec/test_app/config/application.rb
+++ b/spec/test_app/config/application.rb
@@ -1,6 +1,6 @@
 require "action_controller/railtie"
 require "action_view/railtie"
-require "webpacker"
+require "shakapacker"
 
 module TestApp
   class Application < ::Rails::Application
diff --git a/spec/test_app/config/shakapacker.yml b/spec/test_app/config/shakapacker.yml
new file mode 100644
index 000000000..8dc9de404
--- /dev/null
+++ b/spec/test_app/config/shakapacker.yml
@@ -0,0 +1,82 @@
+# Note: You must restart bin/shakapacker-dev-server for changes to take effect
+
+default: &default
+  source_path: app/javascript
+  source_entry_path: entrypoints
+  nested_entries: false
+  public_root_path: public
+  public_output_path: packs
+  cache_path: tmp/shakapacker
+  webpack_compile_output: false
+  webpack_loader: babel
+
+  # Location for manifest.json, defaults to {public_output_path}/manifest.json if unset
+  # manifest_path: public/packs/manifest.json
+
+  # Additional paths webpack should look up modules
+  # ['app/assets', 'engine/foo/app/assets']
+  additional_paths:
+    - app/assets
+    - /etc/yarn
+    - some.config.js
+    - app/elm
+
+  # Reload manifest.json on all requests so we reload latest compiled packs
+  cache_manifest: false
+
+  static_assets_extensions:
+    - .jpg
+    - .jpeg
+    - .png
+    - .gif
+    - .tiff
+    - .ico
+    - .svg
+
+  extensions:
+    - .mjs
+    - .js
+
+development:
+  <<: *default
+  compile: true
+  ensure_consistent_versioning: true
+
+  # Reference: https://webpack.js.org/configuration/dev-server/
+  dev_server:
+    host: localhost
+    port: 3035
+    public: localhost:3035
+    hmr: false
+    overlay: true
+    disable_host_check: true
+    use_local_ip: false
+    pretty: false
+
+test:
+  <<: *default
+  compile: true
+
+  # Compile test packs to a separate directory
+  public_output_path: packs-test
+
+production:
+  <<: *default
+
+  # Production depends on precompilation of packs prior to booting for performance.
+  compile: false
+
+  # Cache manifest.json for performance
+  cache_manifest: true
+
+staging:
+  <<: *default
+
+  # Production depends on precompilation of packs prior to booting for performance.
+  compile: false
+
+  # Cache manifest.json for performance
+  cache_manifest: true
+
+  # Compile staging packs to a separate directory
+  public_output_path: packs-staging
diff --git a/spec/test_app/config/shakapacker_css_extract_ignore_order_warnings.yml b/spec/test_app/config/shakapacker_css_extract_ignore_order_warnings.yml
new file mode 100644
index 000000000..b73770516
--- /dev/null
+++ b/spec/test_app/config/shakapacker_css_extract_ignore_order_warnings.yml
@@ -0,0 +1,84 @@
+# Note: You must restart bin/shakapacker-dev-server for changes to take effect
+
+default: &default
+  source_path: app/javascript
+  source_entry_path: entrypoints
+  nested_entries: true
+  public_root_path: public
+  public_output_path: packs
+  cache_path: tmp/shakapacker
+  webpack_compile_output: false
+  webpack_loader: babel
+  css_extract_ignore_order_warnings: true
+
+  # Location for manifest.json, defaults to {public_output_path}/manifest.json if unset
+  # manifest_path: public/packs/manifest.json
+
+  # Additional paths webpack should look up modules
+  # ['app/assets', 'engine/foo/app/assets']
+  additional_paths:
+    - app/assets
+    - /etc/yarn
+    - some.config.js
+    - app/elm
+
+  # Reload manifest.json on all requests so we reload latest compiled packs
+  cache_manifest: false
+
+  static_assets_extensions:
+    - .jpg
+    - .jpeg
+    - .png
+    - .gif
+    - .tiff
+    - .ico
+    - .svg
+
+  extensions:
+    - .mjs
+    - .js
+
+development:
+  <<: *default
+  compile: true
+  ensure_consistent_versioning: true
+
+  # Reference: https://webpack.js.org/configuration/dev-server/
+  dev_server:
+    https: false
+    host: localhost
+    port: 3035
+    public: localhost:3035
+    hmr: false
+    overlay: true
+    disable_host_check: true
+    use_local_ip: false
+    pretty: false
+
+test:
+  <<: *default
+  compile: true
+
+  # Compile test packs to a separate directory
+  public_output_path: packs-test
+
+production:
+  <<: *default
+
+  # Production depends on precompilation of packs prior to booting for performance.
+  compile: false
+
+  # Cache manifest.json for performance
+  cache_manifest: true
+
+staging:
+  <<: *default
+
+  # Production depends on precompilation of packs prior to booting for performance.
+  compile: false
+
+  # Cache manifest.json for performance
+  cache_manifest: true
+
+  # Compile staging packs to a separate directory
+  public_output_path: packs-staging
diff --git a/spec/test_app/config/shakapacker_defaults_fallback.yml b/spec/test_app/config/shakapacker_defaults_fallback.yml
new file mode 100644
index 000000000..b4ba964e2
--- /dev/null
+++ b/spec/test_app/config/shakapacker_defaults_fallback.yml
@@ -0,0 +1,11 @@
+# Note: You must restart bin/shakapacker-dev-server for changes to take effect
+
+default: &default
+  # cache_manifest will be fetched from bundled defaults
+  shakapacker_precompile: false
+
+staging:
+  <<: *default
+
+production:
+  <<: *default
diff --git a/spec/test_app/config/shakapacker_manifest_path.yml b/spec/test_app/config/shakapacker_manifest_path.yml
new file mode 100644
index 000000000..f6262181d
--- /dev/null
+++ b/spec/test_app/config/shakapacker_manifest_path.yml
@@ -0,0 +1,80 @@
+# Note: You must restart bin/webpack-dev-server for changes to take effect
+
+default: &default
+  source_path: app/javascript
+  source_entry_path: entrypoints
+  public_root_path: public
+  public_output_path: packs
+  cache_path: tmp/shakapacker
+  webpack_compile_output: false
+
+  # Location for manifest.json, defaults to {public_output_path}/manifest.json if unset
+  manifest_path: app/javascript/manifest.json
+
+  # Additional paths webpack should look up modules
+  # ['app/assets', 'engine/foo/app/assets']
+  additional_paths:
+    - app/assets
+    - /etc/yarn
+    - some.config.js
+    - app/elm
+
+  # Reload manifest.json on all requests so we reload latest compiled packs
+  cache_manifest: false
+
+  static_assets_extensions:
+    - .jpg
+    - .jpeg
+    - .png
+    - .gif
+    - .tiff
+    - .ico
+    - .svg
+
+  extensions:
+    - .mjs
+    - .js
+
+development:
+  <<: *default
+  compile: true
+
+  # Reference: https://webpack.js.org/configuration/dev-server/
+  dev_server:
+    https: false
+    host: localhost
+    port: 3035
+    public: localhost:3035
+    hmr: false
+    overlay: true
+    disable_host_check: true
+    use_local_ip: false
+    pretty: false
+
+test:
+  <<: *default
+  compile: true
+
+  # Compile test packs to a separate directory
+  public_output_path: packs-test
+
+production:
+  <<: *default
+
+  # Production depends on precompilation of packs prior to booting for performance.
+  compile: false
+
+  # Cache manifest.json for performance
+  cache_manifest: true
+
+staging:
+  <<: *default
+
+  # Production depends on precompilation of packs prior to booting for performance.
+  compile: false
+
+  # Cache manifest.json for performance
+  cache_manifest: true
+
+  # Compile staging packs to a separate directory
+  public_output_path: packs-staging
diff --git a/spec/test_app/config/shakapacker_nested_entries.yml b/spec/test_app/config/shakapacker_nested_entries.yml
new file mode 100644
index 000000000..52f091ac9
--- /dev/null
+++ b/spec/test_app/config/shakapacker_nested_entries.yml
@@ -0,0 +1,83 @@
+# Note: You must restart bin/shakapacker-dev-server for changes to take effect
+
+default: &default
+  source_path: app/javascript
+  source_entry_path: entrypoints
+  nested_entries: true
+  public_root_path: public
+  public_output_path: packs
+  cache_path: tmp/shakapacker
+  webpack_compile_output: false
+  webpack_loader: babel
+
+  # Location for manifest.json, defaults to {public_output_path}/manifest.json if unset
+  # manifest_path: public/packs/manifest.json
+
+  # Additional paths webpack should look up modules
+  # ['app/assets', 'engine/foo/app/assets']
+  additional_paths:
+    - app/assets
+    - /etc/yarn
+    - some.config.js
+    - app/elm
+
+  # Reload manifest.json on all requests so we reload latest compiled packs
+  cache_manifest: false
+
+  static_assets_extensions:
+    - .jpg
+    - .jpeg
+    - .png
+    - .gif
+    - .tiff
+    - .ico
+    - .svg
+
+  extensions:
+    - .mjs
+    - .js
+
+development:
+  <<: *default
+  compile: true
+  ensure_consistent_versioning: true
+
+  # Reference: https://webpack.js.org/configuration/dev-server/
+  dev_server:
+    https: false
+    host: localhost
+    port: 3035
+    public: localhost:3035
+    hmr: false
+    overlay: true
+    disable_host_check: true
+    use_local_ip: false
+    pretty: false
+
+test:
+  <<: *default
+  compile: true
+
+  # Compile test packs to a separate directory
+  public_output_path: packs-test
+
+production:
+  <<: *default
+
+  # Production depends on precompilation of packs prior to booting for performance.
+  compile: false
+
+  # Cache manifest.json for performance
+  cache_manifest: true
+
+staging:
+  <<: *default
+
+  # Production depends on precompilation of packs prior to booting for performance.
+  compile: false
+
+  # Cache manifest.json for performance
+  cache_manifest: true
+
+  # Compile staging packs to a separate directory
+  public_output_path: packs-staging
diff --git a/spec/test_app/config/shakapacker_no_precompile.yml b/spec/test_app/config/shakapacker_no_precompile.yml
new file mode 100644
index 000000000..7ce51ed1c
--- /dev/null
+++ b/spec/test_app/config/shakapacker_no_precompile.yml
@@ -0,0 +1,7 @@
+# Note: You must restart bin/shakapacker-dev-server for changes to take effect
+
+default: &default
+  shakapacker_precompile: false
+
+production:
+  <<: *default
diff --git a/spec/test_app/config/shakapacker_other_location.yml b/spec/test_app/config/shakapacker_other_location.yml
new file mode 100644
index 000000000..8ea4cfdc4
--- /dev/null
+++ b/spec/test_app/config/shakapacker_other_location.yml
@@ -0,0 +1,85 @@
+# Note: You must restart bin/shakapacker-dev-server for changes to take effect
+
+default: &default
+  source_path: app/javascript
+  source_entry_path: entrypoints
+  public_root_path: public
+  public_output_path: packs
+  cache_path: tmp/cache/shakapacker
+  webpack_compile_output: false
+
+  # Additional paths webpack should look up modules
+  # ['app/assets', 'engine/foo/app/assets']
+  additional_paths:
+    - app/assets
+    - /etc/yarn
+    - some.config.js
+    - app/elm
+
+  # Reload manifest.json on all requests so we reload latest compiled packs
+  cache_manifest: false
+
+  static_assets_extensions:
+    - .jpg
+    - .jpeg
+    - .png
+    - .gif
+    - .tiff
+    - .ico
+    - .svg
+
+  extensions:
+    - .mjs
+    - .js
+
+development:
+  <<: *default
+  compile: true
+
+  # Reference: https://webpack.js.org/configuration/dev-server/
+  dev_server:
+    https: false
+    host: localhost
+    port: 3035
+    public: localhost:3035
+    hmr: false
+    # If HMR is on, CSS will by inlined by delivering it as part of the script payload via style-loader. Be sure
+    # that you add style-loader to your project dependencies.
+    #
+    # If you want to instead deliver CSS via <link> with the mini-extract-css-plugin, set inline_css to false.
+    # In that case, style-loader is not needed as a dependency.
+    #
+    # mini-extract-css-plugin is a required dependency in both cases.
+    inline_css: true
+    overlay: true
+    disable_host_check: true
+    use_local_ip: false
+    pretty: false
+
+test:
+  <<: *default
+  compile: true
+
+  # Compile test packs to a separate directory
+  public_output_path: packs-test
+
+production:
+  <<: *default
+
+  # Production depends on precompilation of packs prior to booting for performance.
+  compile: false
+
+  # Cache manifest.json for performance
+  cache_manifest: true
+
+staging:
+  <<: *default
+
+  # Production depends on precompilation of packs prior to booting for performance.
+  compile: false
+
+  # Cache manifest.json for performance
+  cache_manifest: true
+
+  # Compile staging packs to a separate directory
+  public_output_path: packs-staging
diff --git a/spec/test_app/config/shakapacker_public_root.yml b/spec/test_app/config/shakapacker_public_root.yml
new file mode 100644
index 000000000..701ae8752
--- /dev/null
+++ b/spec/test_app/config/shakapacker_public_root.yml
@@ -0,0 +1,18 @@
+# Note: You must restart bin/shakapacker-dev-server for changes to take effect
+
+default: &default
+  public_root_path: ../public
+
+development:
+  <<: *default
+  compile: true
+
+test:
+  <<: *default
+  compile: true
+  public_output_path: packs-test
+
+production:
+  <<: *default
+  compile: false
+  cache_manifest: true
diff --git a/spec/test_app/config/webpacker_no_precompile.yml b/spec/test_app/config/webpacker_no_precompile.yml
deleted file mode 100644
index 0affe4bb7..000000000
--- a/spec/test_app/config/webpacker_no_precompile.yml
+++ /dev/null
@@ -1,7 +0,0 @@
-# Note: You must restart bin/webpacker-dev-server for changes to take effect
-
-default: &default
-  webpacker_precompile: false
-
-production:
-  <<: *default
diff --git a/spec/version_checker_spec.rb b/spec/version_checker_spec.rb
index b009613f8..a46027cfc 100644
--- a/spec/version_checker_spec.rb
+++ b/spec/version_checker_spec.rb
@@ -1,4 +1,5 @@
-require "webpacker/version"
+require_relative "spec_helper_initializer"
+require "shakapacker/version"
 
 class NodePackageVersionDouble
   attr_reader :raw, :major_minor_patch
@@ -20,10 +21,10 @@ def skip_processing?
 end
 
 describe "VersionChecker" do
-  def check_version(node_package_version, stub_gem_version = Webpacker::VERSION, stub_config = true)
-    version_checker = Webpacker::VersionChecker.new(node_package_version)
+  def check_version(node_package_version, stub_gem_version = Shakapacker::VERSION, stub_config = true)
+    version_checker = Shakapacker::VersionChecker.new(node_package_version)
     allow(version_checker).to receive(:gem_version).and_return(stub_gem_version)
-    allow(Webpacker.config).to receive(:ensure_consistent_versioning?).and_return(stub_config)
+    allow(Shakapacker.config).to receive(:ensure_consistent_versioning?).and_return(stub_config)
 
     version_checker.raise_if_gem_and_node_package_versions_differ
   end
@@ -32,7 +33,7 @@ def check_version(node_package_version, stub_gem_version = Webpacker::VERSION, s
     node_package_version = NodePackageVersionDouble.new(raw: "6.1.0", major_minor_patch: ["6", "1", "0"])
 
     expect { check_version(node_package_version, "6.0.0", false) }
-      .to output(/Webpacker::VersionChecker - Version mismatch/)
+      .to output(/Shakapacker::VersionChecker - Version mismatch/)
       .to_stderr
   end
 
@@ -40,7 +41,7 @@ def check_version(node_package_version, stub_gem_version = Webpacker::VERSION, s
     node_package_version = NodePackageVersionDouble.new(raw: "^6.1.0", major_minor_patch: ["6", "1", "0"], semver_wildcard: true)
 
     expect { check_version(node_package_version, "6.0.0", false) }
-      .to output(/Webpacker::VersionChecker - Semver wildcard without a lockfile detected/)
+      .to output(/Shakapacker::VersionChecker - Semver wildcard without a lockfile detected/)
       .to_stderr
   end
 
@@ -48,28 +49,28 @@ def check_version(node_package_version, stub_gem_version = Webpacker::VERSION, s
     node_package_version = NodePackageVersionDouble.new(raw: "6.1.0", major_minor_patch: ["6", "1", "0"])
 
     expect { check_version(node_package_version, "7.0.0") }
-      .to raise_error(/\*\*ERROR\*\* Webpacker: Webpacker gem and node package versions do not match/)
+      .to raise_error(/\*\*ERROR\*\* Shakapacker: Shakapacker gem and node package versions do not match/)
   end
 
   it "raises exception on different minor version" do
     node_package_version = NodePackageVersionDouble.new(raw: "6.1.0", major_minor_patch: ["6", "1", "0"])
 
     expect { check_version(node_package_version, "6.2.0") }
-      .to raise_error(/\*\*ERROR\*\* Webpacker: Webpacker gem and node package versions do not match/)
+      .to raise_error(/\*\*ERROR\*\* Shakapacker: Shakapacker gem and node package versions do not match/)
   end
 
   it "raises exception on different patch version" do
     node_package_version = NodePackageVersionDouble.new(raw: "6.1.1", major_minor_patch: ["6", "1", "1"])
 
     expect { check_version(node_package_version, "6.1.2") }
-      .to raise_error(/\*\*ERROR\*\* Webpacker: Webpacker gem and node package versions do not match/)
+      .to raise_error(/\*\*ERROR\*\* Shakapacker: Shakapacker gem and node package versions do not match/)
   end
 
   it "raises exception on semver wildcard" do
     node_package_version = NodePackageVersionDouble.new(raw: "^6.0.0", major_minor_patch: ["6", "0", "0"], semver_wildcard: true)
 
     expect { check_version(node_package_version, "6.0.0") }
-      .to raise_error(/\*\*ERROR\*\* Webpacker: Your node package version for shakapacker contains a \^ or ~/)
+      .to raise_error(/\*\*ERROR\*\* Shakapacker: Your node package version for shakapacker contains a \^ or ~/)
   end
 
   it "doesn't raise exception on matching versions" do
@@ -100,7 +101,7 @@ def check_version(node_package_version, stub_gem_version = Webpacker::VERSION, s
 describe "VersionChecker::NodePackageVersion" do
   context "with no yarn.lock file" do
     def node_package_version(fixture_version:)
-      Webpacker::VersionChecker::NodePackageVersion.new(
+      Shakapacker::VersionChecker::NodePackageVersion.new(
         File.expand_path("fixtures/#{fixture_version}_package.json", __dir__),
         "file/does/not/exist",
         "file/does/not/exist"
@@ -270,7 +271,7 @@ def node_package_version(fixture_version:)
 
   context "with yarn.lock v1" do
     def node_package_version(fixture_version:)
-      Webpacker::VersionChecker::NodePackageVersion.new(
+      Shakapacker::VersionChecker::NodePackageVersion.new(
         File.expand_path("fixtures/#{fixture_version}_package.json", __dir__),
         File.expand_path("fixtures/#{fixture_version}_yarn.v1.lock", __dir__),
         "file/does/not/exist"
@@ -440,7 +441,7 @@ def node_package_version(fixture_version:)
 
   context "with yarn.lock v2" do
     def node_package_version(fixture_version:)
-      Webpacker::VersionChecker::NodePackageVersion.new(
+      Shakapacker::VersionChecker::NodePackageVersion.new(
         File.expand_path("fixtures/#{fixture_version}_package.json", __dir__),
         File.expand_path("fixtures/#{fixture_version}_yarn.v2.lock", __dir__),
         "file/does/not/exist"
@@ -610,7 +611,7 @@ def node_package_version(fixture_version:)
 
   context "with package-lock.json v1" do
     def node_package_version(fixture_version:)
-      Webpacker::VersionChecker::NodePackageVersion.new(
+      Shakapacker::VersionChecker::NodePackageVersion.new(
         File.expand_path("fixtures/#{fixture_version}_package.json", __dir__),
         "file/does/not/exist",
         File.expand_path("fixtures/#{fixture_version}_package-lock.v1.json", __dir__),
@@ -780,7 +781,7 @@ def node_package_version(fixture_version:)
 
   context "with package-lock.json v2" do
     def node_package_version(fixture_version:)
-      Webpacker::VersionChecker::NodePackageVersion.new(
+      Shakapacker::VersionChecker::NodePackageVersion.new(
         File.expand_path("fixtures/#{fixture_version}_package.json", __dir__),
         "file/does/not/exist",
         File.expand_path("fixtures/#{fixture_version}_package-lock.v2.json", __dir__),
diff --git a/spec/webpack_runner_spec.rb b/spec/webpack_runner_spec.rb
index 54ddef78a..02d3a6566 100644
--- a/spec/webpack_runner_spec.rb
+++ b/spec/webpack_runner_spec.rb
@@ -1,4 +1,5 @@
-require "webpacker/webpack_runner"
+require_relative "spec_helper_initializer"
+require "shakapacker/webpack_runner"
 
 describe "WebpackRunner" do
   before :all do
@@ -38,7 +39,7 @@ def verify_command(cmd, use_node_modules: true, argv: [])
       cwd = Dir.pwd
       Dir.chdir(test_app_path)
 
-      klass = Webpacker::WebpackRunner
+      klass = Shakapacker::WebpackRunner
       instance = klass.new(argv)
 
       allow(klass).to receive(:new).and_return(instance)
@@ -47,7 +48,7 @@ def verify_command(cmd, use_node_modules: true, argv: [])
 
       klass.run(argv)
 
-      expect(Kernel).to have_received(:exec).with(Webpacker::Compiler.env, *cmd)
+      expect(Kernel).to have_received(:exec).with(Shakapacker::Compiler.env, *cmd)
     ensure
       Dir.chdir(cwd)
     end
diff --git a/spec/webpacker_spec.rb b/spec/webpacker_spec.rb
index c3d6923d3..b864d0636 100644
--- a/spec/webpacker_spec.rb
+++ b/spec/webpacker_spec.rb
@@ -1,6 +1,8 @@
-describe "Webpacker" do
+require_relative "spec_helper_initializer"
+
+describe "Shakapacker" do
   describe "#inline_css?" do
-    let(:dev_server) { instance_double("Webpacker::DevServer") }
+    let(:dev_server) { instance_double("Shakapacker::DevServer") }
 
     before :each do
       allow(dev_server).to receive(:host).and_return("localhost")
@@ -11,47 +13,25 @@
     end
 
     it "returns nil with disabled dev_server" do
-      expect(Webpacker.inlining_css?).to be nil
+      expect(Shakapacker.inlining_css?).to be nil
     end
 
     it "returns true with enabled hmr" do
       allow(dev_server).to receive(:hmr?).and_return(true)
       allow(dev_server).to receive(:inline_css?).and_return(true)
 
-      allow(Webpacker.instance).to receive(:dev_server).and_return(dev_server)
+      allow(Shakapacker.instance).to receive(:dev_server).and_return(dev_server)
 
-      expect(Webpacker.inlining_css?).to be true
+      expect(Shakapacker.inlining_css?).to be true
     end
 
     it "returns false with enabled hmr and explicitly setting inline_css to false" do
       allow(dev_server).to receive(:hmr?).and_return(true)
       allow(dev_server).to receive(:inline_css?).and_return(false)
 
-      allow(Webpacker.instance).to receive(:dev_server).and_return(dev_server)
-
-      expect(Webpacker.inlining_css?).to be false
-    end
-  end
-
-  describe "configurable config" do
-    before do
-      @original_webpacker_config = ENV["WEBPACKER_CONFIG"]
-    end
-
-    after do
-      ENV["WEBPACKER_CONFIG"] = @original_webpacker_config
-    end
-
-    it "allows config file to be changed based on ENV variable" do
-      ENV.delete("WEBPACKER_CONFIG")
-      Webpacker.instance = nil
-      expect(Webpacker.config.config_path.to_s).to eq(Rails.root.join("config/webpacker.yml").to_s)
-    end
+      allow(Shakapacker.instance).to receive(:dev_server).and_return(dev_server)
 
-    it "allows config file to be changed based on ENV variable" do
-      ENV["WEBPACKER_CONFIG"] = "/some/random/path.yml"
-      Webpacker.instance = nil
-      expect(Webpacker.config.config_path.to_s).to eq("/some/random/path.yml")
+      expect(Shakapacker.inlining_css?).to be false
     end
   end