diff --git a/.github/workflows/nix.yml b/.github/workflows/nix.yml
index 6db31f3..6808d05 100644
--- a/.github/workflows/nix.yml
+++ b/.github/workflows/nix.yml
@@ -20,7 +20,7 @@ jobs:
     runs-on: ${{ matrix.os }}
 
     steps:
-      - uses: DeterminateSystems/nix-installer-action@main
+      - uses: DeterminateSystems/nix-installer-action@v21
         with:
           extra-conf: |
             accept-flake-config = true