diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4f8bac8a..69efcf20 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,7 +13,7 @@ jobs:
       fail-fast: false
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v3  # https://github.com/actions/checkout
+      - uses: actions/checkout@v4  # https://github.com/actions/checkout
         with:
           # Only a single commit is fetched by default, for the ref/SHA that triggered the workflow.
           # Set fetch-depth: 0 to fetch all history for all branches and tags.
diff --git a/.github/workflows/codeql-analysis.yml b/.github/workflows/codeql-analysis.yml
index 8d178e96..33957f0e 100644
--- a/.github/workflows/codeql-analysis.yml
+++ b/.github/workflows/codeql-analysis.yml
@@ -32,7 +32,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         # We must fetch at least the immediate parents so that if this is
         # a pull request then we can checkout the head.
diff --git a/.github/workflows/doc.yml b/.github/workflows/doc.yml
index 48e6b4a7..dbad9c07 100644
--- a/.github/workflows/doc.yml
+++ b/.github/workflows/doc.yml
@@ -16,7 +16,7 @@ jobs:
       fail-fast: false
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v3  # https://github.com/actions/checkout
+      - uses: actions/checkout@v4  # https://github.com/actions/checkout
         with:
           # Only a single commit is fetched by default, for the ref/SHA that triggered the workflow.
           # Set fetch-depth: 0 to fetch all history for all branches and tags.
diff --git a/.github/workflows/format.yml b/.github/workflows/format.yml
index 8c8ecb98..d101430d 100644
--- a/.github/workflows/format.yml
+++ b/.github/workflows/format.yml
@@ -16,7 +16,7 @@ jobs:
       fail-fast: false
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v3  # https://github.com/actions/checkout
+      - uses: actions/checkout@v4  # https://github.com/actions/checkout
         with:
           # Only a single commit is fetched by default, for the ref/SHA that triggered the workflow.
           # Set fetch-depth: 0 to fetch all history for all branches and tags.
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index e36f05d7..ea7e4aa6 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -16,7 +16,7 @@ jobs:
       fail-fast: false
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v3  # https://github.com/actions/checkout
+      - uses: actions/checkout@v4  # https://github.com/actions/checkout
         with:
           # Only a single commit is fetched by default, for the ref/SHA that triggered the workflow.
           # Set fetch-depth: 0 to fetch all history for all branches and tags.
diff --git a/.github/workflows/mypy.yml b/.github/workflows/mypy.yml
index 474e1137..01384b92 100644
--- a/.github/workflows/mypy.yml
+++ b/.github/workflows/mypy.yml
@@ -16,7 +16,7 @@ jobs:
       fail-fast: false
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v3  # https://github.com/actions/checkout
+      - uses: actions/checkout@v4  # https://github.com/actions/checkout
         with:
           # Only a single commit is fetched by default, for the ref/SHA that triggered the workflow.
           # Set fetch-depth: 0 to fetch all history for all branches and tags.