diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index 0600d0a..de5ba39 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -5,7 +5,7 @@ on: [push, pull_request]
 jobs:
   build:
 
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-18.04
 
     strategy:
       matrix: