diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 54638ab..32219d8 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -46,7 +46,8 @@ jobs:
 
     name: Elixir ${{ matrix.elixir }} (OTP ${{ matrix.otp }})
 
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
+
 
     steps:
       - name: Checkout repository