diff --git a/.github/workflows/casa.yml b/.github/workflows/casa.yml
index 4930140..ef58692 100644
--- a/.github/workflows/casa.yml
+++ b/.github/workflows/casa.yml
@@ -31,7 +31,7 @@ jobs:
       matrix:
         go_version:
           - 1.17.1
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-18.04
     steps:
 
       #      - name: Get release