diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index bbae39cf..c5f697f6 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -16,7 +16,7 @@ jobs:
 
     steps:
       - name: Check out repository
-        uses: actions/checkout@v3.5.2
+        uses: actions/checkout@v4.1.1
       - name: Install python
         uses: actions/setup-python@v3
       - name: Run pre-commit hooks
@@ -28,16 +28,14 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        pg: ['12', '13', '14', '15', '16']
-        release: [20.04, 22.04]
+        pg: ['11', '12', '13', '14', '15']
+        release: [focal, jammy]
     steps:
       - name: Check out repository
-        uses: actions/checkout@v3.5.2
+        uses: actions/checkout@v4.1.1
 
       - name: Build Docker container
-        run:
-          docker build --build-arg=RELEASE=${{ matrix.release }} --build-arg="PG_VERSION=${{
-          matrix.pg }}" --tag=tester .
+        run: docker build --build-arg=RELEASE=${{ matrix.release }} --tag=tester .
 
       - name: Install from source
         run: docker run --rm tester ./test/ci/install-from-source.bash
diff --git a/nix/sources.json b/nix/sources.json
index 0fd9c603..3e4754f2 100644
--- a/nix/sources.json
+++ b/nix/sources.json
@@ -1,14 +1,14 @@
 {
   "nixpkgs": {
-    "branch": "release-22.11",
+    "branch": "nixpkgs-unstable",
     "description": "Nix Packages collection",
     "homepage": "",
     "owner": "NixOS",
     "repo": "nixpkgs",
-    "rev": "f2e827cbac90dc046f902c96ee9e0da3e45fb452",
-    "sha256": "0405jcvh850d1dwqqxh670irx8pa9dc972r9cavjw4snc7zvdcl2",
+    "rev": "31cd1b4afbaf0b1e81272ee9c31d1ab606503aed",
+    "sha256": "1hd48vkdrj8rgihrkjfhr3amqlf3phjshqyylslb836n6vlp18pp",
     "type": "tarball",
-    "url": "https://github.com/NixOS/nixpkgs/archive/f2e827cbac90dc046f902c96ee9e0da3e45fb452.tar.gz",
+    "url": "https://github.com/NixOS/nixpkgs/archive/31cd1b4afbaf0b1e81272ee9c31d1ab606503aed.tar.gz",
     "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
   }
 }