diff --git a/.github/workflows/backend.yml b/.github/workflows/backend.yml
index 4b6e71ebf..5e7659cad 100644
--- a/.github/workflows/backend.yml
+++ b/.github/workflows/backend.yml
@@ -21,6 +21,7 @@ jobs:
       - uses: actions/setup-python@v5
         with:
           python-version: "3.12"
+          cache: 'pip'
       - name: Lint backend
         run: |
           python -m pip install --upgrade pip
@@ -35,6 +36,7 @@ jobs:
       - uses: actions/setup-python@v5
         with:
           python-version: "3.12"
+          cache: 'pip'
       - name: Build frontend and share library
         shell: bash
         run: make build-frontend
@@ -50,3 +52,17 @@ jobs:
       - name: Pytest
         timeout-minutes: 5
         run: python -m pytest
+
+  test-backend-on-old-python:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.9", "3.10", "3.11"]
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+          cache: 'pip'
+      - name:
+        continue-on-error: True