diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 93c03fe..97a275c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -5,7 +5,7 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
 
     strategy:
       matrix: