diff --git a/.github/workflows/nix-flake-update.yml b/.github/workflows/nix-flake-update.yml
index 15130d7..589d9a4 100644
--- a/.github/workflows/nix-flake-update.yml
+++ b/.github/workflows/nix-flake-update.yml
@@ -13,7 +13,7 @@ jobs:
       - name: Install Nix
         uses: DeterminateSystems/nix-installer-action@v4
       - name: Update flake.lock
-        uses: DeterminateSystems/update-flake-lock@vX
+        uses: DeterminateSystems/update-flake-lock@v20
         with:
           pr-title: "Update flake.lock" # Title of PR to be created
           pr-labels: |                  # Labels to be set on the PR