From 2f4f658c84132d11494ac60c73f5ad597e1844d6 Mon Sep 17 00:00:00 2001
From: Kleis Auke Wolthuizen <github@kleisauke.nl>
Date: Sat, 8 Jul 2023 15:04:55 +0200
Subject: [PATCH] Drop support for .NET Standard 2.0 and Mono

See: https://devblogs.microsoft.com/dotnet/the-future-of-net-standard/
---
 .github/workflows/ci.yml                      |  5 ---
 CHANGELOG.md                                  | 16 +++++--
 README.md                                     |  8 ++--
 build/native/NetVips.Native.linux-arm.nuspec  |  5 +--
 .../native/NetVips.Native.linux-arm64.nuspec  |  5 +--
 .../NetVips.Native.linux-musl-arm64.nuspec    |  3 +-
 .../NetVips.Native.linux-musl-x64.nuspec      |  5 +--
 build/native/NetVips.Native.linux-x64.nuspec  |  5 +--
 build/native/NetVips.Native.nuspec            | 17 +------
 build/native/NetVips.Native.osx-arm64.nuspec  |  3 +-
 build/native/NetVips.Native.osx-x64.nuspec    |  5 +--
 build/native/NetVips.Native.win-arm64.nuspec  |  3 +-
 build/native/NetVips.Native.win-x64.nuspec    |  4 +-
 build/native/NetVips.Native.win-x86.nuspec    |  4 +-
 .../targets/NetVips.Native.linux-arm.targets  | 18 --------
 .../NetVips.Native.linux-arm64.targets        | 18 --------
 .../NetVips.Native.linux-musl-x64.targets     | 18 --------
 .../targets/NetVips.Native.linux-x64.targets  | 18 --------
 .../targets/NetVips.Native.osx-x64.targets    | 18 --------
 build/test-mono.sh                            | 45 -------------------
 docs/docfx.json                               |  2 +-
 .../NetVips.Extensions.csproj                 | 13 ++----
 src/NetVips/ModuleInitializer.cs              |  2 +
 src/NetVips/ModuleInitializerAttribute.cs     |  4 +-
 src/NetVips/NetVips.csproj                    |  6 +--
 tests/NetVips.Tests/NetVips.Tests.csproj      | 19 +-------
 26 files changed, 43 insertions(+), 226 deletions(-)
 delete mode 100644 build/native/targets/NetVips.Native.linux-arm.targets
 delete mode 100644 build/native/targets/NetVips.Native.linux-arm64.targets
 delete mode 100644 build/native/targets/NetVips.Native.linux-musl-x64.targets
 delete mode 100644 build/native/targets/NetVips.Native.linux-x64.targets
 delete mode 100644 build/native/targets/NetVips.Native.osx-x64.targets
 delete mode 100755 build/test-mono.sh

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f0211087..eb1d1231 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -17,10 +17,6 @@ jobs:
           - os: ubuntu-22.04
             container: mcr.microsoft.com/dotnet/sdk:8.0-alpine3.18
             script: ./build.sh
-          # TODO(kleisauke): Re-enable Mono CI when C# 9 features are supported.
-          # - os: ubuntu-22.04
-          #   script: ./build/test-mono.sh
-          #   allow_failures: true
           - os: macos-12
             script: ./build.sh
           - os: windows-2022
@@ -45,5 +41,4 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
       - name: Test
-        continue-on-error: ${{ matrix.allow_failures == true }}
         run: ${{ matrix.script }}
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 96f536de..dd861900 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,11 @@ All notable changes to NetVips will be documented in this file. See [here](CHANG
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/) and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [3.0.0] - TBD
+### Removed
+- Drop support for .NET Standard 2.0 and Mono. NetVips now targets .NET 6 (`net6.0`) and .NET Framework 4.5.2 (`net452`) moving forward.
+  See https://devblogs.microsoft.com/dotnet/the-future-of-net-standard/ for more information.
+
 ## [2.4.2] - 2024-10-13
 ### Fixed
 - Fix incorrect progress reporting on Linux ([#237](https://github.com/kleisauke/net-vips/issues/237)).
@@ -31,7 +36,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ### Changed
 - Update methods/enums for libvips 8.14.
-- The [NetVips.Extensions](https://www.nuget.org/packages/NetVips.Extensions/) package is now only supported on Windows when targeting .NET 6.0 or higher. See https://aka.ms/systemdrawingnonwindows for more information.
+- The [NetVips.Extensions](https://www.nuget.org/packages/NetVips.Extensions/) package is now only supported on Windows when targeting .NET 6.0 or higher.
+  See https://aka.ms/systemdrawingnonwindows for more information.
 
 ### Fixed
 - Ensure compatibility with FreeBSD and variants.
@@ -45,13 +51,15 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ### Changed
 - Update methods/enums for libvips 8.13.
-- Remove internal `VipsSaveable` enum.
 - Avoid throwing general exceptions.
 - Ensure debug and unit tests functions are internal.
 
 ### Fixed
 - Use the correct type for signal handler IDs.
 
+### Removed
+- Remove internal `VipsSaveable` enum.
+
 ## [2.1.0] - 2021-12-02
 ### Added
 - Add `image.SignalHandlerDisconnect()` for disconnecting a signal handler.
@@ -61,7 +69,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Drop internal `ModuleInit.Fody` dependency in favor of the `[ModuleInitializer]` attribute.
 - `image.WriteToBuffer()` tries to use the new target API first.
 - Bump minimum required .NET Framework version to v4.5.2.
-- The [NetVips.Extensions](https://www.nuget.org/packages/NetVips.Extensions/) package is now attributed as a Windows-specific library when targeting .NET 6.0 or higher. See https://aka.ms/systemdrawingnonwindows for more information.
+- The [NetVips.Extensions](https://www.nuget.org/packages/NetVips.Extensions/) package is now attributed as a Windows-specific library when targeting .NET 6.0 or higher.
+  See https://aka.ms/systemdrawingnonwindows for more information.
 
 ### Fixed
 - Ensure recorded delegates are not released too early ([#141](https://github.com/kleisauke/net-vips/issues/141)).
@@ -228,6 +237,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 ### Added
 - First release!
 
+[3.0.0]: https://github.com/kleisauke/net-vips/compare/v2.4.2...v3.0.0
 [2.4.2]: https://github.com/kleisauke/net-vips/compare/v2.4.1...v2.4.2
 [2.4.1]: https://github.com/kleisauke/net-vips/compare/v2.4.0...v2.4.1
 [2.4.0]: https://github.com/kleisauke/net-vips/compare/v2.3.1...v2.4.0
diff --git a/README.md b/README.md
index 1399deed..be9f5ae3 100644
--- a/README.md
+++ b/README.md
@@ -37,8 +37,7 @@ which gives some more background.
 ## Supported platforms
 
 - .NET Framework 4.5.2 and higher
-- .NET Standard 2.0 and higher
-- Mono
+- .NET 6.0 and higher
 
 ## Install
 
@@ -58,7 +57,7 @@ libvips binaries for the most common platforms (see
 | **Linux ARM64v8 musl**<sup>3</sup>  | [![NetVips.Native.linux-musl-arm64-badge]][NetVips.Native.linux-musl-arm64-nuget] |
 | **Linux ARMv7**                     | [![NetVips.Native.linux-arm-badge]][NetVips.Native.linux-arm-nuget]               |
 | **macOS x64**                       | [![NetVips.Native.osx-x64-badge]][NetVips.Native.osx-x64-nuget]                   |
-| **macOS ARM64**<sup>4</sup>         | [![NetVips.Native.osx-arm64-badge]][NetVips.Native.osx-arm64-nuget]               |
+| **macOS ARM64**                     | [![NetVips.Native.osx-arm64-badge]][NetVips.Native.osx-arm64-nuget]               |
 
 [NetVips.Native.win-x64-badge]: https://img.shields.io/nuget/v/NetVips.Native.win-x64.svg
 [NetVips.Native.win-x64-nuget]: https://www.nuget.org/packages/NetVips.Native.win-x64
@@ -83,8 +82,7 @@ libvips binaries for the most common platforms (see
 
 <sup>1</sup> The version number of these NuGet packages is in sync with libvips' version number.  
 <sup>2</sup> Uses glibc as the standard C library (Ubuntu, Debian, etc).  
-<sup>3</sup> Uses musl as the standard C library (Alpine, Gentoo Linux, etc).  
-<sup>4</sup> Requires .NET 6.0 or higher.
+<sup>3</sup> Uses musl as the standard C library (Alpine, Gentoo Linux, etc).
 
 Then just install this package, perhaps:
 
diff --git a/build/native/NetVips.Native.linux-arm.nuspec b/build/native/NetVips.Native.linux-arm.nuspec
index 72caaec9..0451a10c 100644
--- a/build/native/NetVips.Native.linux-arm.nuspec
+++ b/build/native/NetVips.Native.linux-arm.nuspec
@@ -22,9 +22,6 @@
   </metadata>
   <files>
 
-    <!-- The .NET Framework >= 4.6.1 build bits for Mono runtime -->
-    <file src="targets\NetVips.Native.linux-arm.targets" target="build/net461" />
-
     <!-- Include libvips Linux ARM64v8 binaries -->
     <file src="pack\linux-arm\*.so*" target="runtimes/linux-arm/native" />
 
@@ -35,7 +32,7 @@
     <file src="pack\linux-arm\versions.json" />
 
     <!-- A dummy reference which prevents NuGet from adding any compilation references when this package is imported -->
-    <file src="_._" target="lib/netstandard1.0" />
+    <file src="_._" target="lib/net6.0" />
 
   </files>
 </package>
\ No newline at end of file
diff --git a/build/native/NetVips.Native.linux-arm64.nuspec b/build/native/NetVips.Native.linux-arm64.nuspec
index 5d0ab745..851791d1 100644
--- a/build/native/NetVips.Native.linux-arm64.nuspec
+++ b/build/native/NetVips.Native.linux-arm64.nuspec
@@ -22,9 +22,6 @@
   </metadata>
   <files>
 
-    <!-- The .NET Framework >= 4.6.1 build bits for Mono runtime -->
-    <file src="targets\NetVips.Native.linux-arm64.targets" target="build/net461" />
-
     <!-- Include libvips Linux ARM64v8 binaries -->
     <file src="pack\linux-arm64\*.so*" target="runtimes/linux-arm64/native" />
 
@@ -35,7 +32,7 @@
     <file src="pack\linux-arm64\versions.json" />
 
     <!-- A dummy reference which prevents NuGet from adding any compilation references when this package is imported -->
-    <file src="_._" target="lib/netstandard1.0" />
+    <file src="_._" target="lib/net6.0" />
 
   </files>
 </package>
\ No newline at end of file
diff --git a/build/native/NetVips.Native.linux-musl-arm64.nuspec b/build/native/NetVips.Native.linux-musl-arm64.nuspec
index 55078f30..ee36a3ae 100644
--- a/build/native/NetVips.Native.linux-musl-arm64.nuspec
+++ b/build/native/NetVips.Native.linux-musl-arm64.nuspec
@@ -32,8 +32,7 @@
     <file src="pack\linux-musl-arm64\versions.json" />
 
     <!-- A dummy reference which prevents NuGet from adding any compilation references when this package is imported -->
-    <!-- Note: Linux musl ARM64v8 is supported since .NET Core 3.0 (.NET Standard 2.1) -->
-    <file src="_._" target="lib/netstandard2.1" />
+    <file src="_._" target="lib/net6.0" />
 
   </files>
 </package>
\ No newline at end of file
diff --git a/build/native/NetVips.Native.linux-musl-x64.nuspec b/build/native/NetVips.Native.linux-musl-x64.nuspec
index cb10a20e..ae087d69 100644
--- a/build/native/NetVips.Native.linux-musl-x64.nuspec
+++ b/build/native/NetVips.Native.linux-musl-x64.nuspec
@@ -22,9 +22,6 @@
   </metadata>
   <files>
 
-    <!-- The .NET Framework >= 4.6.1 build bits for Mono runtime -->
-    <file src="targets\NetVips.Native.linux-musl-x64.targets" target="build/net461" />
-
     <!-- Include libvips Linux musl x64 binaries -->
     <file src="pack\linux-musl-x64\*.so*" target="runtimes/linux-musl-x64/native" />
 
@@ -35,7 +32,7 @@
     <file src="pack\linux-musl-x64\versions.json" />
 
     <!-- A dummy reference which prevents NuGet from adding any compilation references when this package is imported -->
-    <file src="_._" target="lib/netstandard1.0" />
+    <file src="_._" target="lib/net6.0" />
 
   </files>
 </package>
\ No newline at end of file
diff --git a/build/native/NetVips.Native.linux-x64.nuspec b/build/native/NetVips.Native.linux-x64.nuspec
index 044dd606..caa04483 100644
--- a/build/native/NetVips.Native.linux-x64.nuspec
+++ b/build/native/NetVips.Native.linux-x64.nuspec
@@ -22,9 +22,6 @@
   </metadata>
   <files>
 
-    <!-- The .NET Framework >= 4.6.1 build bits for Mono runtime -->
-    <file src="targets\NetVips.Native.linux-x64.targets" target="build/net461" />
-
     <!-- Include libvips Linux x64 binaries -->
     <file src="pack\linux-x64\*.so*" target="runtimes/linux-x64/native" />
 
@@ -35,7 +32,7 @@
     <file src="pack\linux-x64\versions.json" />
 
     <!-- A dummy reference which prevents NuGet from adding any compilation references when this package is imported -->
-    <file src="_._" target="lib/netstandard1.0" />
+    <file src="_._" target="lib/net6.0" />
 
   </files>
 </package>
\ No newline at end of file
diff --git a/build/native/NetVips.Native.nuspec b/build/native/NetVips.Native.nuspec
index 2e157b2e..b655f72b 100644
--- a/build/native/NetVips.Native.nuspec
+++ b/build/native/NetVips.Native.nuspec
@@ -21,33 +21,20 @@
 
     <!-- dependencies -->
     <dependencies>
-	  <!-- In-sync with netstandard2.0 below except for NetVips.Native.win-arm64, NetVips.Native.linux-musl-arm64 and NetVips.Native.osx-arm64 -->
-      <group targetFramework="netstandard2.1">
+      <group targetFramework="net6.0">
         <dependency id="NetVips.Native.linux-x64" version="$version$" include="native" />
         <dependency id="NetVips.Native.linux-musl-x64" version="$version$" include="native" />
-        <!-- Linux musl ARM64v8 is supported since .NET Core 3.0 (.NET Standard 2.1) -->
         <dependency id="NetVips.Native.linux-musl-arm64" version="$version$" include="native" />
         <dependency id="NetVips.Native.linux-arm" version="$version$" include="native" />
         <dependency id="NetVips.Native.linux-arm64" version="$version$" include="native" />
         <dependency id="NetVips.Native.osx-x64" version="$version$" include="native" />
-        <!-- macOS ARM64 (Apple Silicon) is supported on .NET 6.0, but Mono has back-ported this to .NET Standard 2.1 -->
         <dependency id="NetVips.Native.osx-arm64" version="$version$" include="native" />
         <dependency id="NetVips.Native.win-x64" version="$version$" include="native" />
         <dependency id="NetVips.Native.win-x86" version="$version$" include="native" />
-        <!-- Windows ARM64 is supported since .NET 5.0 and back-ported to .NET Core 3.1 (.NET Standard 2.1) -->
         <dependency id="NetVips.Native.win-arm64" version="$version$" include="native" />
       </group>
-      <group targetFramework="netstandard2.0">
-        <dependency id="NetVips.Native.linux-x64" version="$version$" include="native" />
-        <dependency id="NetVips.Native.linux-musl-x64" version="$version$" include="native" />
-        <dependency id="NetVips.Native.linux-arm" version="$version$" include="native" />
-        <dependency id="NetVips.Native.linux-arm64" version="$version$" include="native" />
-        <dependency id="NetVips.Native.osx-x64" version="$version$" include="native" />
-        <dependency id="NetVips.Native.win-x64" version="$version$" include="native" />
-        <dependency id="NetVips.Native.win-x86" version="$version$" include="native" />
-      </group>
       <group targetFramework="net452">
-        <!-- Only .NET Framework/Mono needs to include the build directory containing the .targets file -->
+        <!-- Only .NET Framework needs to include the build directory containing the .targets file -->
         <dependency id="NetVips.Native.win-x64" version="$version$" include="native, build" />
         <dependency id="NetVips.Native.win-x86" version="$version$" include="native, build" />
       </group>
diff --git a/build/native/NetVips.Native.osx-arm64.nuspec b/build/native/NetVips.Native.osx-arm64.nuspec
index 299280d1..74bf7cd9 100644
--- a/build/native/NetVips.Native.osx-arm64.nuspec
+++ b/build/native/NetVips.Native.osx-arm64.nuspec
@@ -32,8 +32,7 @@
     <file src="pack\osx-arm64\versions.json" />
 
     <!-- A dummy reference which prevents NuGet from adding any compilation references when this package is imported -->
-    <!-- Note: macOS ARM64 (Apple Silicon) is supported on .NET 6.0, but Mono has back-ported this to .NET Standard 2.1 -->
-    <file src="_._" target="lib/netstandard2.1" />
+    <file src="_._" target="lib/net6.0" />
 
   </files>
 </package>
\ No newline at end of file
diff --git a/build/native/NetVips.Native.osx-x64.nuspec b/build/native/NetVips.Native.osx-x64.nuspec
index 799d6e04..ce4a5866 100644
--- a/build/native/NetVips.Native.osx-x64.nuspec
+++ b/build/native/NetVips.Native.osx-x64.nuspec
@@ -22,9 +22,6 @@
   </metadata>
   <files>
 
-    <!-- The .NET Framework >= 4.6.1 build bits for Mono runtime -->
-    <file src="targets\NetVips.Native.osx-x64.targets" target="build/net461" />
-
     <!-- Include libvips macOS x64 binaries -->
     <file src="pack\osx-x64\*.dylib" target="runtimes/osx-x64/native" />
 
@@ -35,7 +32,7 @@
     <file src="pack\osx-x64\versions.json" />
 
     <!-- A dummy reference which prevents NuGet from adding any compilation references when this package is imported -->
-    <file src="_._" target="lib/netstandard1.0" />
+    <file src="_._" target="lib/net6.0" />
 
   </files>
 </package>
\ No newline at end of file
diff --git a/build/native/NetVips.Native.win-arm64.nuspec b/build/native/NetVips.Native.win-arm64.nuspec
index 190a4722..b9d39acf 100644
--- a/build/native/NetVips.Native.win-arm64.nuspec
+++ b/build/native/NetVips.Native.win-arm64.nuspec
@@ -32,8 +32,7 @@
     <file src="pack\win-arm64\versions.json" />
 
     <!-- A dummy reference which prevents NuGet from adding any compilation references when this package is imported -->
-    <!-- Note: Windows ARM64 is supported since .NET 5.0 and back-ported to .NET Core 3.1 (.NET Standard 2.1) -->
-    <file src="_._" target="lib/netstandard2.1" />
+    <file src="_._" target="lib/net6.0" />
 
   </files>
 </package>
\ No newline at end of file
diff --git a/build/native/NetVips.Native.win-x64.nuspec b/build/native/NetVips.Native.win-x64.nuspec
index 1be73f0b..3ff799a0 100644
--- a/build/native/NetVips.Native.win-x64.nuspec
+++ b/build/native/NetVips.Native.win-x64.nuspec
@@ -22,8 +22,8 @@
   </metadata>
   <files>
 
-    <!-- The .NET Framework >= 4.5 build bits -->
-    <file src="targets\NetVips.Native.win-x64.targets" target="build/net45" />
+    <!-- The .NET Framework >= 4.5.2 build bits -->
+    <file src="targets\NetVips.Native.win-x64.targets" target="build/net452" />
 
     <!-- Include libvips Windows x64 binaries -->
     <file src="pack\win-x64\*.dll" target="runtimes/win-x64/native" />
diff --git a/build/native/NetVips.Native.win-x86.nuspec b/build/native/NetVips.Native.win-x86.nuspec
index 4c208d2a..3d53872a 100644
--- a/build/native/NetVips.Native.win-x86.nuspec
+++ b/build/native/NetVips.Native.win-x86.nuspec
@@ -22,8 +22,8 @@
   </metadata>
   <files>
 
-    <!-- The .NET Framework >= 4.5 build bits -->
-    <file src="targets\NetVips.Native.win-x86.targets" target="build/net45" />
+    <!-- The .NET Framework >= 4.5.2 build bits -->
+    <file src="targets\NetVips.Native.win-x86.targets" target="build/net452" />
 
     <!-- Include libvips Windows x86 binaries -->
     <file src="pack\win-x86\*.dll" target="runtimes/win-x86/native" />
diff --git a/build/native/targets/NetVips.Native.linux-arm.targets b/build/native/targets/NetVips.Native.linux-arm.targets
deleted file mode 100644
index 242b3a50..00000000
--- a/build/native/targets/NetVips.Native.linux-arm.targets
+++ /dev/null
@@ -1,18 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-
-    <PropertyGroup>
-        <LibvipsOutputBase Condition="'$(LibvipsOutputBase)' == ''"></LibvipsOutputBase>
-        <!-- EnsureTrailingSlash is only available since VS 2017 -->
-        <LibvipsOutputBase Condition="'$(LibvipsOutputBase)' != '' AND !HasTrailingSlash('$(LibvipsOutputBase)')">$(LibvipsOutputBase)\</LibvipsOutputBase>
-    </PropertyGroup>
-
-    <!-- Mono still needs to copy the native dependencies to the output directory -->
-    <ItemGroup Condition="'$(MSBuildRuntimeType)' == 'Mono'">
-        <None Include="$(MSBuildThisFileDirectory)..\..\runtimes\linux-arm\native\*">
-            <Link>$(LibvipsOutputBase)%(Filename)%(Extension)</Link>
-            <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-        </None>
-    </ItemGroup>
-
-</Project>
\ No newline at end of file
diff --git a/build/native/targets/NetVips.Native.linux-arm64.targets b/build/native/targets/NetVips.Native.linux-arm64.targets
deleted file mode 100644
index 62c13e13..00000000
--- a/build/native/targets/NetVips.Native.linux-arm64.targets
+++ /dev/null
@@ -1,18 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-
-    <PropertyGroup>
-        <LibvipsOutputBase Condition="'$(LibvipsOutputBase)' == ''"></LibvipsOutputBase>
-        <!-- EnsureTrailingSlash is only available since VS 2017 -->
-        <LibvipsOutputBase Condition="'$(LibvipsOutputBase)' != '' AND !HasTrailingSlash('$(LibvipsOutputBase)')">$(LibvipsOutputBase)\</LibvipsOutputBase>
-    </PropertyGroup>
-
-    <!-- Mono still needs to copy the native dependencies to the output directory -->
-    <ItemGroup Condition="'$(MSBuildRuntimeType)' == 'Mono'">
-        <None Include="$(MSBuildThisFileDirectory)..\..\runtimes\linux-arm64\native\*">
-            <Link>$(LibvipsOutputBase)%(Filename)%(Extension)</Link>
-            <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-        </None>
-    </ItemGroup>
-
-</Project>
\ No newline at end of file
diff --git a/build/native/targets/NetVips.Native.linux-musl-x64.targets b/build/native/targets/NetVips.Native.linux-musl-x64.targets
deleted file mode 100644
index 84c5c801..00000000
--- a/build/native/targets/NetVips.Native.linux-musl-x64.targets
+++ /dev/null
@@ -1,18 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-
-    <PropertyGroup>
-        <LibvipsOutputBase Condition="'$(LibvipsOutputBase)' == ''"></LibvipsOutputBase>
-        <!-- EnsureTrailingSlash is only available since VS 2017 -->
-        <LibvipsOutputBase Condition="'$(LibvipsOutputBase)' != '' AND !HasTrailingSlash('$(LibvipsOutputBase)')">$(LibvipsOutputBase)\</LibvipsOutputBase>
-    </PropertyGroup>
-
-    <!-- Mono still needs to copy the native dependencies to the output directory -->
-    <ItemGroup Condition="'$(MSBuildRuntimeType)' == 'Mono'">
-        <None Include="$(MSBuildThisFileDirectory)..\..\runtimes\linux-musl-x64\native\*">
-            <Link>$(LibvipsOutputBase)%(Filename)%(Extension)</Link>
-            <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-        </None>
-    </ItemGroup>
-
-</Project>
\ No newline at end of file
diff --git a/build/native/targets/NetVips.Native.linux-x64.targets b/build/native/targets/NetVips.Native.linux-x64.targets
deleted file mode 100644
index 1696b03c..00000000
--- a/build/native/targets/NetVips.Native.linux-x64.targets
+++ /dev/null
@@ -1,18 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-
-    <PropertyGroup>
-        <LibvipsOutputBase Condition="'$(LibvipsOutputBase)' == ''"></LibvipsOutputBase>
-        <!-- EnsureTrailingSlash is only available since VS 2017 -->
-        <LibvipsOutputBase Condition="'$(LibvipsOutputBase)' != '' AND !HasTrailingSlash('$(LibvipsOutputBase)')">$(LibvipsOutputBase)\</LibvipsOutputBase>
-    </PropertyGroup>
-
-    <!-- Mono still needs to copy the native dependencies to the output directory -->
-    <ItemGroup Condition="'$(MSBuildRuntimeType)' == 'Mono'">
-        <None Include="$(MSBuildThisFileDirectory)..\..\runtimes\linux-x64\native\*">
-            <Link>$(LibvipsOutputBase)%(Filename)%(Extension)</Link>
-            <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-        </None>
-    </ItemGroup>
-
-</Project>
\ No newline at end of file
diff --git a/build/native/targets/NetVips.Native.osx-x64.targets b/build/native/targets/NetVips.Native.osx-x64.targets
deleted file mode 100644
index 60abfd51..00000000
--- a/build/native/targets/NetVips.Native.osx-x64.targets
+++ /dev/null
@@ -1,18 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-
-    <PropertyGroup>
-        <LibvipsOutputBase Condition="'$(LibvipsOutputBase)' == ''"></LibvipsOutputBase>
-        <!-- EnsureTrailingSlash is only available since VS 2017 -->
-        <LibvipsOutputBase Condition="'$(LibvipsOutputBase)' != '' AND !HasTrailingSlash('$(LibvipsOutputBase)')">$(LibvipsOutputBase)\</LibvipsOutputBase>
-    </PropertyGroup>
-
-    <!-- Mono still needs to copy the native dependencies to the output directory -->
-    <ItemGroup Condition="'$(MSBuildRuntimeType)' == 'Mono'">
-        <None Include="$(MSBuildThisFileDirectory)..\..\runtimes\osx-x64\native\*">
-            <Link>$(LibvipsOutputBase)%(Filename)%(Extension)</Link>
-            <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-        </None>
-    </ItemGroup>
-
-</Project>
\ No newline at end of file
diff --git a/build/test-mono.sh b/build/test-mono.sh
deleted file mode 100755
index 7265bd1f..00000000
--- a/build/test-mono.sh
+++ /dev/null
@@ -1,45 +0,0 @@
-#!/usr/bin/env bash
-
-set -eo pipefail
-
-###########################################################################
-# CONFIGURATION
-###########################################################################
-
-BUILD_DIR=$(cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd)
-SCRIPT_DIR=$(dirname "$BUILD_DIR")
-
-XUNIT_RUNNER="$SCRIPT_DIR/packages/xunit.runner.console/tools/net472/xunit.console.exe"
-BUILD_PROJECT_FILE="$SCRIPT_DIR/tests/NetVips.Tests/NetVips.Tests.csproj"
-DLL_FILE="$SCRIPT_DIR/tests/NetVips.Tests/bin/Release/net472/NetVips.Tests.dll"
-
-# https://github.com/dotnet/runtime/issues/11540
-if [ "$(uname)" == "Darwin" ]; then
-    export DYLD_LIBRARY_PATH=$(dirname "$DLL_FILE")${DYLD_LIBRARY_PATH:+:$DYLD_LIBRARY_PATH}
-elif [ "$(expr substr $(uname -s) 1 5)" == "Linux" ]; then
-    export LD_LIBRARY_PATH=$(dirname "$DLL_FILE")${LD_LIBRARY_PATH:+:$LD_LIBRARY_PATH}
-fi
-
-# Parse arguments
-while [ $# -gt 0 ]; do
-    case $1 in
-        --global-vips) USE_NUGET_BINARIES=false ;;
-        *) echo "Unknown parameter passed: $1" >&2; exit 1 ;;
-    esac
-    shift
-done
-
-###########################################################################
-# EXECUTION
-###########################################################################
-
-if ! [ -x "$(command -v mono)" ]; then
-    echo 'Error: mono is not installed.' >&2
-    exit 1
-fi
-
-echo "Mono version $(mono --version)"
-
-nuget install xunit.runner.console -ExcludeVersion -o packages
-msbuild $BUILD_PROJECT_FILE -t:build -restore -p:TargetFramework="net472" -p:Configuration=Release -p:TestWithNuGetBinaries=${USE_NUGET_BINARIES:-true} -nodeReuse:false
-mono $XUNIT_RUNNER $DLL_FILE
diff --git a/docs/docfx.json b/docs/docfx.json
index 1ef8538a..78ded446 100644
--- a/docs/docfx.json
+++ b/docs/docfx.json
@@ -15,7 +15,7 @@
       ],
       "dest": "obj/temp/api",
       "properties": {
-        "TargetFramework": "netstandard2.0"
+        "TargetFramework": "net6.0"
       }
     }
   ],
diff --git a/src/NetVips.Extensions/NetVips.Extensions.csproj b/src/NetVips.Extensions/NetVips.Extensions.csproj
index a76ff696..77bfb5a0 100644
--- a/src/NetVips.Extensions/NetVips.Extensions.csproj
+++ b/src/NetVips.Extensions/NetVips.Extensions.csproj
@@ -3,8 +3,8 @@
   <Import Project="..\..\build\common.props" />
 
   <PropertyGroup>
-    <TargetFrameworks>net6.0;netstandard2.0;net461</TargetFrameworks>
-    <TargetFrameworks Condition="!$([MSBuild]::IsOSPlatform('Windows'))">netstandard2.0</TargetFrameworks>
+    <TargetFrameworks>net6.0;net461</TargetFrameworks>
+    <TargetFrameworks Condition="!$([MSBuild]::IsOSPlatform('Windows'))">net6.0</TargetFrameworks>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageId>NetVips.Extensions</PackageId>
     <AssemblyName>NetVips.Extensions</AssemblyName>
@@ -20,17 +20,10 @@
     <ProjectReference Include="..\..\src\NetVips\NetVips.csproj" />
   </ItemGroup>
 
-  <ItemGroup Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)','net6.0'))">
+  <ItemGroup Condition="'$(TargetFrameworkIdentifier)' != '.NETFramework'">
     <PackageReference Include="System.Drawing.Common" Version="8.0.10" />
   </ItemGroup>
 
-  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
-    <!-- For .NET Standard 2.0; constrain the version to 5.0.3 as later versions are Windows-only.
-         https://aka.ms/systemdrawingnonwindows
-    -->
-    <PackageReference Include="System.Drawing.Common" Version="[5.0.3]" />
-  </ItemGroup>
-
   <ItemGroup Condition="'$(TargetFrameworkIdentifier)' == '.NETFramework'">
     <Reference Include="System" />
     <Reference Include="System.Drawing" />
diff --git a/src/NetVips/ModuleInitializer.cs b/src/NetVips/ModuleInitializer.cs
index 43b184b0..1f9e971b 100644
--- a/src/NetVips/ModuleInitializer.cs
+++ b/src/NetVips/ModuleInitializer.cs
@@ -25,7 +25,9 @@ public static class ModuleInitializer
         /// <summary>
         /// Initializes the module.
         /// </summary>
+#pragma warning disable CA2255
         [System.Runtime.CompilerServices.ModuleInitializer]
+#pragma warning restore CA2255
         public static void Initialize()
         {
             try
diff --git a/src/NetVips/ModuleInitializerAttribute.cs b/src/NetVips/ModuleInitializerAttribute.cs
index 47e805e2..06d6cea3 100644
--- a/src/NetVips/ModuleInitializerAttribute.cs
+++ b/src/NetVips/ModuleInitializerAttribute.cs
@@ -1,6 +1,6 @@
-// This file enables ModuleInitializer, a C# 9 feature to work with .NET Standard/Framework.
+// This file enables ModuleInitializer, a C# 9 feature to work with .NET Framework.
 
-#if NETSTANDARD || NETFRAMEWORK
+#if NETFRAMEWORK
 namespace System.Runtime.CompilerServices
 {
     /// <inheritdoc />
diff --git a/src/NetVips/NetVips.csproj b/src/NetVips/NetVips.csproj
index 0410589b..4753f587 100644
--- a/src/NetVips/NetVips.csproj
+++ b/src/NetVips/NetVips.csproj
@@ -3,8 +3,8 @@
   <Import Project="..\..\build\common.props" />
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;net452</TargetFrameworks>
-    <TargetFrameworks Condition="!$([MSBuild]::IsOSPlatform('Windows'))">netstandard2.0</TargetFrameworks>
+    <TargetFrameworks>net6.0;net452</TargetFrameworks>
+    <TargetFrameworks Condition="!$([MSBuild]::IsOSPlatform('Windows'))">net6.0</TargetFrameworks>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <ApplicationIcon />
     <OutputType>Library</OutputType>
@@ -39,7 +39,7 @@
     <InternalsVisibleTo Include="$(AssemblyName).Samples" />
   </ItemGroup>
 
-  <ItemGroup>
+  <ItemGroup Condition="'$(TargetFrameworkIdentifier)' == '.NETFramework'">
     <PackageReference Include="System.Buffers" Version="4.5.1" />
   </ItemGroup>
 
diff --git a/tests/NetVips.Tests/NetVips.Tests.csproj b/tests/NetVips.Tests/NetVips.Tests.csproj
index 6dda37ec..d6cd2e3a 100644
--- a/tests/NetVips.Tests/NetVips.Tests.csproj
+++ b/tests/NetVips.Tests/NetVips.Tests.csproj
@@ -14,30 +14,15 @@
     <TestWithNuGetBinaries>false</TestWithNuGetBinaries>
   </PropertyGroup>
 
-  <!-- https://github.com/mono/mono/issues/15569 -->
-  <PropertyGroup Condition="'$(MSBuildRuntimeType)' == 'Mono'">
-    <RuntimeIdentifier Condition="$([MSBuild]::IsOSPlatform('Linux'))">linux-x64</RuntimeIdentifier>
-    <RuntimeIdentifier Condition="$([MSBuild]::IsOSPlatform('OSX'))">osx-x64</RuntimeIdentifier>
-  </PropertyGroup>
-
   <ItemGroup>
-    <PackageReference Include="Microsoft.CSharp" Version="4.7.0" Condition="'$(MSBuildRuntimeType)' == 'Mono'" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />
-    <PackageReference Include="xunit" Version="2.9.2" />
-    <PackageReference Include="Xunit.SkippableFact" Version="1.4.13" />
-  </ItemGroup>
-
-  <ItemGroup Condition="'$(TestWithNuGetBinaries)' == 'true' And '$(MSBuildRuntimeType)' == 'Mono'">
-    <PackageReference Include="NetVips.Native.linux-x64" Version="8.15.3" Condition="$([MSBuild]::IsOSPlatform('Linux'))" />
-    <PackageReference Include="NetVips.Native.osx-x64" Version="8.15.3" Condition="$([MSBuild]::IsOSPlatform('OSX'))" />
-  </ItemGroup>
-
-  <ItemGroup Condition="'$(MSBuildRuntimeType)' != 'Mono'">
     <PackageReference Include="NetVips.Native" Version="8.15.3" Condition="'$(TestWithNuGetBinaries)' == 'true'" />
+    <PackageReference Include="xunit" Version="2.9.2" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
+    <PackageReference Include="Xunit.SkippableFact" Version="1.4.13" />
   </ItemGroup>
 
   <ItemGroup>