diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 2fd3f1e..b5e07c7 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -5,32 +5,51 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        nix:
+          - name: 2.3.16
+            url: https://releases.nixos.org/nix/nix-2.3.16/install
+          - name: 2.4
+            url: https://releases.nixos.org/nix/nix-2.4/install
+          - name: 2.5pre
+            url: https://github.com/numtide/nix-unstable-installer/releases/download/nix-2.5pre20211026_5667822/install
     steps:
       - uses: actions/checkout@v2.3.5
-      - uses: cachix/install-nix-action@v14.1
+      - uses: cachix/install-nix-action@v15
         with:
-          install_url: https://github.com/numtide/nix-unstable-installer/releases/download/nix-2.4pre20210823_af94b54/install
+          install_url: ${{ matrix.nix.url }}
           extra_nix_config: |
             experimental-features = nix-command flakes
 
       - run: nix flake check
-      - run: nix build
-
-  build-compat:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v2.3.5
-      - uses: cachix/install-nix-action@v14.1
-      - run: nix-build
+        if: ${{ !contains(matrix.nix.name, '2.3') }}
+      - name: Build Colmena
+        run: nix build -L
+        if: ${{ !contains(matrix.nix.name, '2.3') }}
+      - name: Build Colmena with flake-compat
+        run: nix-build
 
   tests:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        nix:
+          - name: 2.3.16
+            url: https://releases.nixos.org/nix/nix-2.3.16/install
+          - name: 2.4
+            url: https://releases.nixos.org/nix/nix-2.4/install
+          - name: 2.5pre
+            url: https://github.com/numtide/nix-unstable-installer/releases/download/nix-2.5pre20211026_5667822/install
     steps:
       - uses: actions/checkout@v2.3.5
-      - uses: cachix/install-nix-action@v14.1
+      - uses: cachix/install-nix-action@v15
         with:
-          install_url: https://github.com/numtide/nix-unstable-installer/releases/download/nix-2.4pre20210823_af94b54/install
+          install_url: ${{ matrix.nix.url }}
           extra_nix_config: |
             experimental-features = nix-command flakes
 
       - run: nix-shell --run "cargo test"
+        if: ${{ !contains(matrix.nix.name, '2.3') }}
+      - run: nix-shell --run "cargo test -- --skip flake"
+        if: ${{ contains(matrix.nix.name, '2.3') }}
diff --git a/flake.nix b/flake.nix
index bcaae4a..0434d85 100644
--- a/flake.nix
+++ b/flake.nix
@@ -28,7 +28,6 @@
 
     devShell = pkgs.mkShell {
       inputsFrom = [ defaultPackage ];
-      buildInputs = [ pkgs.nixUnstable ];
       shellHook = ''
         export NIX_PATH=nixpkgs=${pkgs.path}
       '';