diff --git a/.github/workflows/CI.yaml b/.github/workflows/CI.yaml
index 55f00bf..cdc6286 100644
--- a/.github/workflows/CI.yaml
+++ b/.github/workflows/CI.yaml
@@ -28,7 +28,7 @@ jobs:
       fail-fast: true
       matrix:
         python-version: ["3.6", "3.7", "3.8"]
-        runs-on: ["ubuntu-22.04"]
+        runs-on: ["ubuntu-20.04"]
     uses: ./.github/workflows/run_tests.yaml
     with:
       python-version: ${{ matrix.python-version }}