diff --git a/.github/workflows/haskell-ci.yml b/.github/workflows/haskell-ci.yml
index 7049ab5d..83c33173 100644
--- a/.github/workflows/haskell-ci.yml
+++ b/.github/workflows/haskell-ci.yml
@@ -143,7 +143,7 @@ jobs:
           chmod a+x $HOME/.cabal/bin/cabal-plan
           cabal-plan --version
       - name: checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           path: source
       - name: initial cabal.project for sdist
diff --git a/.github/workflows/nix-flake.yml b/.github/workflows/nix-flake.yml
index 74789fdc..faf4394d 100644
--- a/.github/workflows/nix-flake.yml
+++ b/.github/workflows/nix-flake.yml
@@ -18,7 +18,7 @@ jobs:
     name: Nix on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - uses: wimpysworld/nothing-but-nix@main
       if: runner.os == 'Linux'
       with:
@@ -53,7 +53,7 @@ jobs:
     name: Nix on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - uses: wimpysworld/nothing-but-nix@main
       if: runner.os == 'Linux'
       with:
diff --git a/.github/workflows/update-flake-lock.yml b/.github/workflows/update-flake-lock.yml
index d4d6bc99..cbf7728f 100644
--- a/.github/workflows/update-flake-lock.yml
+++ b/.github/workflows/update-flake-lock.yml
@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Install Nix
         uses: DeterminateSystems/nix-installer-action@main
       - name: Update flake.lock