diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 41bf3e095..10607bec0 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -13,7 +13,7 @@ jobs:
     permissions:
       id-token: write
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
 
       - name: Install uv and set up the Python version
         uses: astral-sh/setup-uv@v5
diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index e4f0d857b..c79b06ac5 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -14,7 +14,7 @@ jobs:
         python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
 
     - name: Set revision
       run: |
@@ -24,21 +24,23 @@ jobs:
     # Compile each Fast Downward revision only once and cache the results.
     - name: Cache revisions
       id: cache-revisions
-      uses: actions/cache@v3
+      uses: actions/cache@v5
       with:
         path: revision-cache
         key: ${{ matrix.os }}-revision-cache-${{ env.GIT_DOWNWARD_REV }}
 
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@v6
       with:
         python-version: ${{ matrix.python-version }}
         allow-prereleases: true
 
     - name: Install Apptainer
-      uses: eWaterCycle/setup-apptainer@v2
-      with:
-        apptainer-version: 1.3.6
+      run: |
+        wget --no-verbose \
+          https://github.com/apptainer/apptainer/releases/download/v1.3.6/apptainer_1.3.6_amd64.deb \
+          -O /tmp/apptainer.deb
+        sudo apt-get install -y /tmp/apptainer.deb
 
     - name: Show environment
       run: |