diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 0f6e295..693e518 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -12,7 +12,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Check version numbers
         run: ./version.sh
@@ -40,7 +40,7 @@ jobs:
            fi
       
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Build wheels
         uses: pypa/cibuildwheel@v2.8.1
@@ -77,7 +77,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Use OCaml ${{ matrix.ocaml-compiler }}
         uses: avsm/setup-ocaml@v2