diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index f542cd5..1d616f9 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -15,9 +15,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Install Nix
-        uses: cachix/install-nix-action@v22
+        uses: cachix/install-nix-action@v27
         with:
           github_access_token: ${{ secrets.GITHUB_TOKEN }}
       - name: Prepare devShell
@@ -41,10 +41,10 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       # For builtins.
       - name: Install Nix
-        uses: cachix/install-nix-action@v22
+        uses: cachix/install-nix-action@v27
         with:
           github_access_token: ${{ secrets.GITHUB_TOKEN }}
           nix_path: nixpkgs=channel:nixpkgs-unstable
@@ -65,9 +65,9 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Install Nix
-        uses: cachix/install-nix-action@v22
+        uses: cachix/install-nix-action@v27
         with:
           github_access_token: ${{ secrets.GITHUB_TOKEN }}
       - name: Flake check
@@ -84,12 +84,12 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         # flake-compat doesn't support shallow repo.
         with:
           fetch-depth: 0
       - name: Install Nix
-        uses: cachix/install-nix-action@v22
+        uses: cachix/install-nix-action@v27
         with:
           nix_path: nixpkgs=channel:nixpkgs-unstable
           github_access_token: ${{ secrets.GITHUB_TOKEN }}
diff --git a/.github/workflows/future-proof.yaml b/.github/workflows/future-proof.yaml
index 714f2b2..2d63453 100644
--- a/.github/workflows/future-proof.yaml
+++ b/.github/workflows/future-proof.yaml
@@ -19,9 +19,9 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Install Nix
-        uses: cachix/install-nix-action@v22
+        uses: cachix/install-nix-action@v27
         with:
           github_access_token: ${{ secrets.GITHUB_TOKEN }}
       - name: Flake update
@@ -40,7 +40,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Install cargo-outdated
         uses: dtolnay/install@cargo-outdated
       - name: cargo-outdated