diff --git a/.github/workflows/workflow.yml b/.github/workflows/workflow.yml
index fee5ae79..f9590517 100644
--- a/.github/workflows/workflow.yml
+++ b/.github/workflows/workflow.yml
@@ -14,7 +14,7 @@ jobs:
     runs-on: ${{ matrix.operating-system }}
     strategy:
       matrix:
-        operating-system: [ubuntu-latest, windows-latest]
+        operating-system: [ubuntu-20.04, windows-latest]
     steps:
     - name: Checkout
       uses: actions/checkout@v2