diff --git a/.github/workflows/auto-release.yml b/.github/workflows/auto-release.yml
index 367f7ce..6a8eecb 100644
--- a/.github/workflows/auto-release.yml
+++ b/.github/workflows/auto-release.yml
@@ -9,7 +9,7 @@ jobs:
   auto-release:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Release
         uses: softprops/action-gh-release@v2
diff --git a/.github/workflows/cpp.yml b/.github/workflows/cpp.yml
index 02a4152..7899567 100644
--- a/.github/workflows/cpp.yml
+++ b/.github/workflows/cpp.yml
@@ -15,7 +15,7 @@ jobs:
   format:
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Install clang-format
         run: |
@@ -39,7 +39,7 @@ jobs:
   lint:
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Install cpplint
         run: pip install cpplint
diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index 5f78acd..1760b5c 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -13,7 +13,7 @@ jobs:
   build_and_deploy:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Set up Python
         uses: actions/setup-python@v5
diff --git a/.github/workflows/document-test.yml b/.github/workflows/document-test.yml
index 15ec071..21c6159 100644
--- a/.github/workflows/document-test.yml
+++ b/.github/workflows/document-test.yml
@@ -27,7 +27,7 @@ jobs:
       CC: ${{ matrix.compiler.cc }}-${{ matrix.compiler.ver }}
       CXX: ${{ matrix.compiler.cxx }}-${{ matrix.compiler.ver }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           submodules: true
 
diff --git a/.github/workflows/full-test.yml b/.github/workflows/full-test.yml
index 13fcd4c..21d76ef 100644
--- a/.github/workflows/full-test.yml
+++ b/.github/workflows/full-test.yml
@@ -52,7 +52,7 @@ jobs:
       CC: ${{ matrix.compiler.cc }}-${{ matrix.compiler.ver }}
       CXX: ${{ matrix.compiler.cxx }}-${{ matrix.compiler.ver }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           submodules: true
 
@@ -92,7 +92,7 @@ jobs:
       matrix:
         osver: [13, 14, 15]
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           submodules: true