diff --git a/.github/workflows/build-dev.yml b/.github/workflows/build-dev.yml
index 8589aa17b..fc9b9c565 100644
--- a/.github/workflows/build-dev.yml
+++ b/.github/workflows/build-dev.yml
@@ -16,7 +16,7 @@ jobs:
 #    runs-on: ubuntu-latest
 #
 #    steps:
-#      - uses: actions/checkout@v1
+#      - uses: actions/checkout@v2.3.4
 #      - uses: actions/setup-dotnet@v1
 #        with:
 #          dotnet-version: '3.1.201'
@@ -28,7 +28,7 @@ jobs:
     runs-on: windows-latest
     
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2.3.4
 
     - name: Run tests on Windows for all targets
       run: dotnet test -c Release 
@@ -38,7 +38,7 @@ jobs:
     needs: [test-win] #,test-netcore-linux]
 
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2.3.4
 
     - name: Create and push NuGet package
       run: |
diff --git a/.github/workflows/codeql-analysis.yml b/.github/workflows/codeql-analysis.yml
index f051f7c3a..b18fcc13e 100644
--- a/.github/workflows/codeql-analysis.yml
+++ b/.github/workflows/codeql-analysis.yml
@@ -23,7 +23,7 @@ jobs:
 
       - name: Checkout repository
         id: checkout_repo
-        uses: actions/checkout@v2
+        uses: actions/checkout@v2.3.4
 
       - name: Initialize CodeQL
         id: init_codeql
diff --git a/.github/workflows/pull-request.yml b/.github/workflows/pull-request.yml
index ab42fe09f..d1d73d206 100644
--- a/.github/workflows/pull-request.yml
+++ b/.github/workflows/pull-request.yml
@@ -7,7 +7,7 @@ jobs:
     runs-on: windows-latest
 
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v2.3.4
       - uses: actions/setup-dotnet@v1.8.0
         with:
           dotnet-version: '3.1.201'
@@ -19,7 +19,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v2.3.4
 
       - name: Vuepress
         run: |