diff --git a/.github/workflows/test_pdoc.yml b/.github/workflows/test_pdoc.yml
index 4ccb703..61ca8b6 100644
--- a/.github/workflows/test_pdoc.yml
+++ b/.github/workflows/test_pdoc.yml
@@ -9,7 +9,7 @@ jobs:
 
     steps:
       - name: Set up Git repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - uses: ./actions/pdoc
         with:
diff --git a/.github/workflows/test_tex.yml b/.github/workflows/test_tex.yml
index 49b91cd..434b753 100644
--- a/.github/workflows/test_tex.yml
+++ b/.github/workflows/test_tex.yml
@@ -9,7 +9,7 @@ jobs:
 
     steps:
       - name: Set up Git repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - uses: ./actions/latex
         with:
diff --git a/actions/book/action.yml b/actions/book/action.yml
index 44d36e5..27efc5d 100644
--- a/actions/book/action.yml
+++ b/actions/book/action.yml
@@ -20,7 +20,7 @@ runs:
 
   steps:
     - name: Check out repository
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Download all artifacts
       uses: actions/download-artifact@v3
diff --git a/actions/setup-environment/action.yml b/actions/setup-environment/action.yml
index 9635110..6685cc3 100644
--- a/actions/setup-environment/action.yml
+++ b/actions/setup-environment/action.yml
@@ -28,7 +28,7 @@ runs:
   using: "composite"
   steps:
     - name: Check out repository
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Set up Python
       uses: actions/setup-python@v4