diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 2eb56ff5..bbcb4176 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -29,7 +29,7 @@ jobs:
           opam install -y num ledit camlp-streams ocamlfind
 
       - name: Checkout this repo
-        uses: actions/checkout@v2
+        uses: actions/checkout@v6
         with:
           path: hol-light
 
@@ -54,7 +54,7 @@ jobs:
           opam init --disable-sandboxing
 
       - name: Checkout this repo
-        uses: actions/checkout@v2
+        uses: actions/checkout@v6
         with:
           path: hol-light
 
@@ -95,7 +95,7 @@ jobs:
           opam init --disable-sandboxing
 
       - name: Checkout this repo
-        uses: actions/checkout@v2
+        uses: actions/checkout@v6
         with:
           path: hol-light
 
diff --git a/.github/workflows/mcp.yml b/.github/workflows/mcp.yml
index 5bf7f73f..3bc45ac6 100644
--- a/.github/workflows/mcp.yml
+++ b/.github/workflows/mcp.yml
@@ -17,7 +17,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Install opam & build HOL Light
         run: |