diff --git a/README.md b/README.md
index 5885d7c..983679f 100644
--- a/README.md
+++ b/README.md
@@ -121,7 +121,7 @@ on: push
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     name: OTP ${{matrix.otp}} / Elixir ${{matrix.elixir}}
     strategy:
       matrix:
@@ -145,7 +145,7 @@ on: push
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     name: Erlang/OTP ${{matrix.otp}} / rebar3 ${{matrix.rebar3}}
     strategy:
       matrix: