diff --git a/.github/workflows/flake-checker.yml b/.github/workflows/flake-checker.yml
index ebb5660..2870650 100644
--- a/.github/workflows/flake-checker.yml
+++ b/.github/workflows/flake-checker.yml
@@ -16,6 +16,6 @@ jobs:
       - uses: actions/checkout@v5
         with:
           fetch-depth: 0
-      - uses: DeterminateSystems/nix-installer-action@v19
+      - uses: DeterminateSystems/nix-installer-action@v21
       - uses: DeterminateSystems/magic-nix-cache-action@v13
       - uses: DeterminateSystems/flake-checker-action@v12
diff --git a/.github/workflows/flake-updater.yml b/.github/workflows/flake-updater.yml
index c214391..1d6b35e 100644
--- a/.github/workflows/flake-updater.yml
+++ b/.github/workflows/flake-updater.yml
@@ -13,7 +13,7 @@ jobs:
       - uses: actions/checkout@v5
         with:
           fetch-depth: 0
-      - uses: DeterminateSystems/nix-installer-action@v19
+      - uses: DeterminateSystems/nix-installer-action@v21
       - uses: DeterminateSystems/magic-nix-cache-action@v13
       - uses: DeterminateSystems/update-flake-lock@v27
         with:
diff --git a/.github/workflows/test-build-stream-sprout.yml b/.github/workflows/test-build-stream-sprout.yml
index 299d6d6..d4b7d43 100644
--- a/.github/workflows/test-build-stream-sprout.yml
+++ b/.github/workflows/test-build-stream-sprout.yml
@@ -57,7 +57,7 @@ jobs:
       - name: "Checkout 🥡"
         uses: "actions/checkout@v5"
       - name: "Install Nix ❄️"
-        uses: "DeterminateSystems/nix-installer-action@v19"
+        uses: "DeterminateSystems/nix-installer-action@v21"
       - name: "Enable Magic Nix Cache 🪄"
         uses: "DeterminateSystems/magic-nix-cache-action@v13"
       - name: "Build & Test .nix ❄️"