diff --git a/.github/workflows/gh-pages.yml b/.github/workflows/gh-pages.yml
index 6471f4d..2759625 100644
--- a/.github/workflows/gh-pages.yml
+++ b/.github/workflows/gh-pages.yml
@@ -17,7 +17,7 @@ jobs:
       group: ${{ github.workflow }}
     steps:
       - uses: actions/checkout@v4
-      - uses: cachix/install-nix-action@v26
+      - uses: cachix/install-nix-action@V27
         with:
           extra_nix_config: |
             accept-flake-config = true
diff --git a/.github/workflows/update-flake-lock.yml b/.github/workflows/update-flake-lock.yml
index 6bf8c45..9d72779 100644
--- a/.github/workflows/update-flake-lock.yml
+++ b/.github/workflows/update-flake-lock.yml
@@ -11,7 +11,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
       - name: Install Nix
-        uses: cachix/install-nix-action@v26
+        uses: cachix/install-nix-action@V27
         with:
           # nix run in 2.20 seems broken: Exec format error
           install_url: https://nixos.org/releases/nix/nix-2.19.4/install