diff --git a/.github/workflows/linting.yml b/.github/workflows/linting.yml
index ac459b87cad9..f5c3eaf1dcce 100644
--- a/.github/workflows/linting.yml
+++ b/.github/workflows/linting.yml
@@ -10,12 +10,12 @@ concurrency:
 
 jobs:
   python-linting:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2
 
     - name: set up Python
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@42375524e23c412d93fb67b49958b491fce71c38 # v5.4.0
       with:
         python-version: 3.8
 
diff --git a/.github/workflows/unit_tests.yml b/.github/workflows/unit_tests.yml
index c98e5144b2be..79c0ba72027e 100644
--- a/.github/workflows/unit_tests.yml
+++ b/.github/workflows/unit_tests.yml
@@ -10,27 +10,27 @@ concurrency:
 
 jobs:
   test-suite:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     strategy:
       matrix:
-        python: [3.6, '3.11']
+        python: ['3.9', '3.11']
         modules_tool: [Lmod-8.6.8]
         module_syntax: [Lua, Tcl]
       fail-fast: false
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2
       with:
         fetch-depth: 0 # Required for git merge-base to work
 
     - name: Cache source files in /tmp/sources
       id: cache-sources
-      uses: actions/cache@v4
+      uses: actions/cache@d4323d4df104b026a6aa633fdb11d772146be0bf # 4.2.2
       with:
         path: /tmp/sources
         key: eb-sourcepath
 
     - name: set up Python
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@42375524e23c412d93fb67b49958b491fce71c38 # v5.4.0
       with:
         python-version: ${{matrix.python}}
         architecture: x64
@@ -153,10 +153,10 @@ jobs:
       matrix:
         python: [3.6, '3.11']
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2
 
     - name: set up Python
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@42375524e23c412d93fb67b49958b491fce71c38 # v5.4.0
       with:
         python-version: ${{matrix.python}}