diff --git a/.github/workflows/bandit.yml b/.github/workflows/bandit.yml
index 126939d9c..1eb90c4f8 100644
--- a/.github/workflows/bandit.yml
+++ b/.github/workflows/bandit.yml
@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Bandit security check for code
         uses: akaihola/bandit-report-artifacts@use-config
diff --git a/.github/workflows/codespell.yml b/.github/workflows/codespell.yml
index 6a5bbf0fe..481c9baf7 100644
--- a/.github/workflows/codespell.yml
+++ b/.github/workflows/codespell.yml
@@ -8,5 +8,5 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: codespell-project/actions-codespell@master
diff --git a/.github/workflows/darker-flake8.yml b/.github/workflows/darker-flake8.yml
index 73c876206..9fa3f02de 100644
--- a/.github/workflows/darker-flake8.yml
+++ b/.github/workflows/darker-flake8.yml
@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - name: Run Darker's own GitHub action straight from the repository
diff --git a/.github/workflows/flake8.yml b/.github/workflows/flake8.yml
index 9198446dd..be7cda22a 100644
--- a/.github/workflows/flake8.yml
+++ b/.github/workflows/flake8.yml
@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: TrueBrain/actions-flake8@v2
         with:
           plugins: >
diff --git a/.github/workflows/help-in-readme.yml b/.github/workflows/help-in-readme.yml
index 669bde931..738834fea 100644
--- a/.github/workflows/help-in-readme.yml
+++ b/.github/workflows/help-in-readme.yml
@@ -5,7 +5,7 @@ jobs:
   help-in-readme:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - run: pip install '.[flynt,isort]'
       - name: Verify that README contains output of darker --help
         shell: python
diff --git a/.github/workflows/isort.yml b/.github/workflows/isort.yml
index 97fc714af..b6e7961a2 100644
--- a/.github/workflows/isort.yml
+++ b/.github/workflows/isort.yml
@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
       - run: pip install 'isort>=5.0.1'
       - uses: wearerequired/lint-action@v2.1.0
diff --git a/.github/workflows/mypy.yml b/.github/workflows/mypy.yml
index b37d36461..62f2480ee 100644
--- a/.github/workflows/mypy.yml
+++ b/.github/workflows/mypy.yml
@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
       - run: |
           pip install -U \
diff --git a/.github/workflows/pylint.yml b/.github/workflows/pylint.yml
index b1e23b13c..4587c1a3f 100644
--- a/.github/workflows/pylint.yml
+++ b/.github/workflows/pylint.yml
@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
       - name: Install dependencies for running Pylint
         run: |
diff --git a/.github/workflows/python-package.yml b/.github/workflows/python-package.yml
index 9518fb75d..6f18d75a2 100644
--- a/.github/workflows/python-package.yml
+++ b/.github/workflows/python-package.yml
@@ -19,7 +19,7 @@ jobs:
     outputs:
       wheel-path: ${{ steps.get-darker-version.outputs.wheel-path }}
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
       - name: Install wheel
         run: python -m pip install wheel
@@ -54,7 +54,7 @@ jobs:
     needs:
       - build-wheel
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: cachix/install-nix-action@v22
         with:
           nix_path: nixpkgs=channel:nixos-unstable
@@ -104,7 +104,7 @@ jobs:
     needs:
       - build-wheel
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0
           # need full history since Pytest runs Darker itself below
@@ -144,7 +144,7 @@ jobs:
     needs:
       - build-wheel
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
       - name: Install twine
         run: python -m pip install twine
diff --git a/.github/workflows/pyupgrade.yml b/.github/workflows/pyupgrade.yml
index a9f1d762f..0273248ec 100644
--- a/.github/workflows/pyupgrade.yml
+++ b/.github/workflows/pyupgrade.yml
@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
       - run: pip install pyupgrade
       - name: Ensure modern Python style using pyupgrade
diff --git a/.github/workflows/safety.yml b/.github/workflows/safety.yml
index df7f1e297..4aab1bfd4 100644
--- a/.github/workflows/safety.yml
+++ b/.github/workflows/safety.yml
@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
       - run: pip install -U pip-tools
       - run: pip-compile setup.cfg
diff --git a/.github/workflows/test-bump-version.yml b/.github/workflows/test-bump-version.yml
index 3661da637..d0cd59d5d 100644
--- a/.github/workflows/test-bump-version.yml
+++ b/.github/workflows/test-bump-version.yml
@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
 
       - name: Make sure that `bump_version.py` still finds all version strings
diff --git a/.github/workflows/test-future.yml b/.github/workflows/test-future.yml
index 28a07e53c..189f097e8 100644
--- a/.github/workflows/test-future.yml
+++ b/.github/workflows/test-future.yml
@@ -12,7 +12,7 @@ jobs:
   test-future:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           ref: 'master'
           fetch-depth: 0
diff --git a/.github/workflows/yaml-lint.yml b/.github/workflows/yaml-lint.yml
index ba25d1bf3..4b8fc446d 100644
--- a/.github/workflows/yaml-lint.yml
+++ b/.github/workflows/yaml-lint.yml
@@ -5,6 +5,6 @@ jobs:
   lintAllTheThings:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: yaml-lint
         uses: ibiqlik/action-yamllint@v3
diff --git a/CHANGES.rst b/CHANGES.rst
index 078594cde..e689f0911 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -25,6 +25,7 @@ Fixed
 - ``show_capture`` option in Pytest configuration.
 - Ignore some linter messages by recent versions of linters used in CI builds.
 - Fix compatibility with Pygments 2.17.2 in unit tests.
+- Update `actions/checkout@v3` to `actions/checkout@v4` in CI builds.
 
 
 1.7.2_ - 2023-07-12
diff --git a/README.rst b/README.rst
index d0dc95ea2..0383eb5a3 100644
--- a/README.rst
+++ b/README.rst
@@ -729,7 +729,7 @@ Create a file named ``.github/workflows/darker.yml`` inside your repository with
      lint:
        runs-on: ubuntu-latest
        steps:
-         - uses: actions/checkout@v3
+         - uses: actions/checkout@v4
            with:
              fetch-depth: 0 
          - uses: actions/setup-python@v5