diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index f342540..a31337f 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -5,48 +5,68 @@ on:
     branches:
       - master
 
+env:
+  nixpkgs_channel: nixpkgs=channel:nixos-23.11
+  oldest_supported_installer: nix-2.8.0
+  # Fetch new versions from the Nix CI run: https://github.com/NixOS/nix/blob/master/.github/workflows/ci.yml
+  # TODO: add pinning upstream or rethink this
+  pinned_installer_hash: zfzfrbb59jsqrfkldwj8drcr9nhhc49k
+
 jobs:
   simple-build:
     strategy:
+      fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os:
+        - ubuntu-latest
+        - macos-latest
+        - macos-13
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v4
     - name: Install Nix
       uses: ./
       with:
-        nix_path: nixpkgs=channel:nixos-22.11
+        nix_path: ${{ env.nixpkgs_channel }}
     - run: nix-env -iA cachix -f https://cachix.org/api/v1/install
     - run: cat /etc/nix/nix.conf
     # cachix should be available and be able to configure a cache
     - run: cachix use cachix
     - run: nix-build test.nix
+
   custom-nix-path:
     strategy:
+      fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os:
+        - ubuntu-latest
+        - macos-latest
+        - macos-13
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v4
     - name: Install Nix
       uses: ./
       with:
-        nix_path: nixpkgs=channel:nixos-20.03
-    - run: test $NIX_PATH == "nixpkgs=channel:nixos-20.03"
+        nix_path: ${{ env.nixpkgs_channel }}
+    - run: test $NIX_PATH == '${{ env.nixpkgs_channel }}'
     - run: nix-build test.nix
 
   extra-nix-config:
     strategy:
+      fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os:
+        - ubuntu-latest
+        - macos-latest
+        - macos-13
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v4
     - name: Install Nix
       uses: ./
       with:
-        nix_path: nixpkgs=channel:nixos-22.11
+        nix_path: ${{ env.nixpkgs_channel }}
         extra_nix_config: |
           sandbox = relaxed
     - run: cat /etc/nix/nix.conf
@@ -54,8 +74,12 @@ jobs:
 
   flakes:
     strategy:
+      fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os:
+        - ubuntu-latest
+        - macos-latest
+        - macos-13
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v4
@@ -65,37 +89,45 @@ jobs:
 
   installer-options:
     strategy:
+      fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os:
+        - ubuntu-latest
+        # - macos-latest missing installer for aarch64-darwin
+        - macos-13
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v4
     - name: Install Nix
       uses: ./
       with:
-        nix_path: nixpkgs=channel:nixos-22.11
+        nix_path: ${{ env.nixpkgs_channel }}
         install_options: --tarball-url-prefix https://nixos-nix-install-tests.cachix.org/serve
-        install_url: https://nixos-nix-install-tests.cachix.org/serve/s62m7lc0q0mz2mxxm9q0kkrcg90njzhq/install
+        install_url: https://nixos-nix-install-tests.cachix.org/serve/${{ env.pinned_installer_hash }}/install
     - run: nix-build test.nix
 
   oldest-supported-installer:
     strategy:
-        matrix:
-          os: [ubuntu-latest, macos-latest]
+      fail-fast: false
+      matrix:
+        os:
+        - ubuntu-latest
+        - macos-latest
+        - macos-13
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v4
     - name: Install Nix
       uses: ./
       with:
-        nix_path: nixpkgs=channel:nixos-22.11
-        install_url: https://releases.nixos.org/nix/nix-2.8.0/install
+        nix_path: ${{ env.nixpkgs_channel }}
+        install_url: https://releases.nixos.org/nix/${{ env.oldest_supported_installer }}/install
     - run: nix-build test.nix
 
   act-support:
     strategy:
-        matrix:
-          os: [ubuntu-latest]
+      matrix:
+        os: [ubuntu-latest]
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v4