diff --git a/.github/workflows/release-tip.yml b/.github/workflows/release-tip.yml
index 47abaea52..1df4ec38e 100644
--- a/.github/workflows/release-tip.yml
+++ b/.github/workflows/release-tip.yml
@@ -81,7 +81,7 @@ jobs:
         fetch-depth: 0
 
     # Install Nix and use that to run our tests so our environment matches exactly.
-    - uses: cachix/install-nix-action@v20
+    - uses: cachix/install-nix-action@v21
       with:
         nix_path: nixpkgs=channel:nixos-unstable
 
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index d8fc1d2b4..f18cf6e14 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -31,7 +31,7 @@ jobs:
         fetch-depth: 0
 
     # Install Nix and use that to run our tests so our environment matches exactly.
-    - uses: cachix/install-nix-action@v20
+    - uses: cachix/install-nix-action@v21
       with:
         nix_path: nixpkgs=channel:nixos-unstable
 
@@ -54,7 +54,7 @@ jobs:
         fetch-depth: 0
 
     # Install Nix and use that to run our tests so our environment matches exactly.
-    - uses: cachix/install-nix-action@v20
+    - uses: cachix/install-nix-action@v21
       with:
         nix_path: nixpkgs=channel:nixos-unstable
 
@@ -82,7 +82,7 @@ jobs:
         fetch-depth: 0
 
     # Install Nix and use that to run our tests so our environment matches exactly.
-    - uses: cachix/install-nix-action@v20
+    - uses: cachix/install-nix-action@v21
       with:
         nix_path: nixpkgs=channel:nixos-unstable