diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 464c165..dcef77d 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -8,7 +8,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [windows-latest, ubuntu-latest, macos-latest]
+        os: [windows-latest, ubuntu-20.04, macos-latest]
       fail-fast: false
     steps:
       - name: Expose GitHub Runtime