diff --git a/.github/workflows/cache.yml b/.github/workflows/cache.yml
index 25d6b24..31fe3ab 100644
--- a/.github/workflows/cache.yml
+++ b/.github/workflows/cache.yml
@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       
       # Use unified composite action for complete environment setup
       - name: Setup Complete Lecture Environment
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4806928..1503837 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -5,7 +5,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Setup Anaconda
         uses: conda-incubator/setup-miniconda@v3
         with:
diff --git a/.github/workflows/linkcheck.yml b/.github/workflows/linkcheck.yml
index 7b8a21e..4682921 100644
--- a/.github/workflows/linkcheck.yml
+++ b/.github/workflows/linkcheck.yml
@@ -13,7 +13,7 @@ jobs:
     steps:
       # Checkout the live site (html)
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           ref: gh-pages
       - name: Link Checker
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 62ed329..20a409b 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Setup Anaconda
         uses: conda-incubator/setup-miniconda@v3
         with: