diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 3d30815a..3aa21eab 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -5,7 +5,7 @@ on: [push, pull_request]
 jobs:
   build:
     name: build (Python ${{ matrix.python-version }}, Django ${{ matrix.django-version }})
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     strategy:
       fail-fast: false
       matrix: