diff --git a/.github/workflows/build-then-cache.yaml b/.github/workflows/build-then-cache.yaml
index 32b7f25..e504e29 100644
--- a/.github/workflows/build-then-cache.yaml
+++ b/.github/workflows/build-then-cache.yaml
@@ -9,8 +9,8 @@ jobs:
     runs-on: ubuntu-24.04-arm
     steps:
       - uses: actions/checkout@v4
-      - uses: DeterminateSystems/nix-installer-action@main
-      - uses: DeterminateSystems/flake-checker-action@main
+      - uses: DeterminateSystems/nix-installer-action@v16
+      - uses: DeterminateSystems/flake-checker-action@v9
       - uses: ryanccn/attic-action@v0
         with:
           endpoint: ${{ secrets.ATTIC_ENDPOINT }}
@@ -25,8 +25,8 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v4
-      - uses: DeterminateSystems/nix-installer-action@main
-      - uses: DeterminateSystems/flake-checker-action@main
+      - uses: DeterminateSystems/nix-installer-action@v16
+      - uses: DeterminateSystems/flake-checker-action@v9
       - uses: ryanccn/attic-action@v0
         with:
           endpoint: ${{ secrets.ATTIC_ENDPOINT }}
@@ -38,8 +38,8 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v4
-      - uses: DeterminateSystems/nix-installer-action@main
-      - uses: DeterminateSystems/flake-checker-action@main
+      - uses: DeterminateSystems/nix-installer-action@v16
+      - uses: DeterminateSystems/flake-checker-action@v9
       - uses: ryanccn/attic-action@v0
         with:
           endpoint: ${{ secrets.ATTIC_ENDPOINT }}
diff --git a/.github/workflows/proactive-update.yaml b/.github/workflows/proactive-update.yaml
index 604a691..9fe68d4 100644
--- a/.github/workflows/proactive-update.yaml
+++ b/.github/workflows/proactive-update.yaml
@@ -12,8 +12,8 @@ jobs:
     runs-on: ubuntu-24.04-arm
     steps:
       - uses: actions/checkout@v4
-      - uses: DeterminateSystems/nix-installer-action@main
-      - uses: DeterminateSystems/flake-checker-action@main
+      - uses: DeterminateSystems/nix-installer-action@v16
+      - uses: DeterminateSystems/flake-checker-action@v9
       - uses: ryanccn/attic-action@v0
         with:
           endpoint: ${{ secrets.ATTIC_ENDPOINT }}
@@ -28,8 +28,8 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v4
-      - uses: DeterminateSystems/nix-installer-action@main
-      - uses: DeterminateSystems/flake-checker-action@main
+      - uses: DeterminateSystems/nix-installer-action@v16
+      - uses: DeterminateSystems/flake-checker-action@v9
       - uses: ryanccn/attic-action@v0
         with:
           endpoint: ${{ secrets.ATTIC_ENDPOINT }}