diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
index ad56b185..235105dc 100644
--- a/.github/workflows/check.yml
+++ b/.github/workflows/check.yml
@@ -13,7 +13,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2.3.3
+        uses: actions/checkout@v2.3.4
 
       - name: Set up Python 3.x
         uses: actions/setup-python@v2
diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index b55b2fb7..74e2f0f8 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -13,7 +13,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2.3.3
+        uses: actions/checkout@v2.3.4
 
       # See https://github.com/warner/python-versioneer/issues/206
       - name: Fetch all history for all tags and branches
diff --git a/.github/workflows/format-command.yml b/.github/workflows/format-command.yml
index 1924e478..5974645a 100644
--- a/.github/workflows/format-command.yml
+++ b/.github/workflows/format-command.yml
@@ -10,7 +10,7 @@ jobs:
   black:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
         with:
           token: ${{ secrets.PAT }}
           repository: ${{ github.event.client_payload.pull_request.head.repo.full_name }}
diff --git a/.github/workflows/pypi-publish.yml b/.github/workflows/pypi-publish.yml
index feefc9fd..7d09e47a 100644
--- a/.github/workflows/pypi-publish.yml
+++ b/.github/workflows/pypi-publish.yml
@@ -14,7 +14,7 @@ jobs:
     if: github.repository == 'seisman/HinetPy'
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v2.3.4
 
     - name: Set up Python
       uses: actions/setup-python@v2
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 43c135fc..04730563 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -31,7 +31,7 @@ jobs:
           access_token: ${{ github.token }}
 
       - name: Checkout
-        uses: actions/checkout@v2.3.3
+        uses: actions/checkout@v2.3.4
 
       # See https://github.com/warner/python-versioneer/issues/206
       - name: Fetch all history for all tags and branches