diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index b0f4154..8cc2572 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -11,54 +11,6 @@ on:
 
 
 jobs:
-  # --- tests running on Ubuntu 20.04 -----------------------------------------
-  tests-py36:
-    # "ubuntu-latest" does not have Python 3.6
-    runs-on: ubuntu-20.04
-    timeout-minutes: 10
-
-    steps:
-      - uses: actions/checkout@v4
-      - name: Set up Python 3.6
-        uses: actions/setup-python@v5
-        with:
-          python-version: "3.6"
-
-      - name: Install dependencies
-        run: |
-          pip install --upgrade pip setuptools wheel
-          pip install -e .[testing]
-
-      - name: Run test suite
-        run: |
-          pytest
-
-
-  # --- testing non-ancient versions ------------------------------------------
-  tests-py3:
-    runs-on: ubuntu-latest
-    timeout-minutes: 10
-
-    strategy:
-      fail-fast: false
-      matrix:
-        python-version: [3.7, 3.8, 3.9, "3.10", "3.11", "3.12", "3.13", pypy3.9]
-
-    steps:
-    - uses: actions/checkout@v4
-    - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v5
-      with:
-        python-version: ${{ matrix.python-version }}
-
-    - name: Install dependencies
-      run: |
-        pip install --upgrade pip setuptools wheel
-        pip install -e .[testing]
-
-    - name: Run test suite
-      run: |
-        pytest
 
   # --- testing on Windows ------------------------------------------
   tests-windows:
@@ -68,7 +20,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
+        python-version: ["3.9"]
 
     steps:
     - uses: actions/checkout@v4
@@ -84,4 +36,4 @@ jobs:
 
     - name: Run test suite
       run: |
-        pytest
+        pytest tests/enqueue_message_test.py::test_can_store_message_on_disk_before_sending