diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7bc692c5..18953abe 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -20,7 +20,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
 
       - name: lean action
         uses: leanprover/lean-action@v1
@@ -35,7 +35,7 @@ jobs:
     if: github.ref == 'refs/heads/main'
     steps:
       - name: checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
 
       - name: lean action
         uses: leanprover/lean-action@v1
diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index bff03797..b37bcf13 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -26,7 +26,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
 
       - name: Install elan
         run: |
diff --git a/.github/workflows/devcontainer.yml b/.github/workflows/devcontainer.yml
index 5b2e0ee5..14c51013 100644
--- a/.github/workflows/devcontainer.yml
+++ b/.github/workflows/devcontainer.yml
@@ -22,7 +22,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
 
       - name: Set up Node.js
         uses: actions/setup-node@v5
diff --git a/.github/workflows/sponsor.yml b/.github/workflows/sponsor.yml
index dfdf8971..54617783 100644
--- a/.github/workflows/sponsor.yml
+++ b/.github/workflows/sponsor.yml
@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repo
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
 
       - name: GitHub Sponsors README Action
         uses: JamesIves/github-sponsors-readme-action@v1
diff --git a/.github/workflows/update.yml b/.github/workflows/update.yml
index 80675076..4f133a77 100644
--- a/.github/workflows/update.yml
+++ b/.github/workflows/update.yml
@@ -11,7 +11,7 @@ jobs:
     if: github.repository_owner == 'lean-ja'
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
       - name: Update Lean project
         uses: leanprover-community/lean-update@main
         with: