diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index 3d2121b68d..f5a1eac8a0 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -5,7 +5,7 @@ on: [push, pull_request]
 jobs:
     build:
         name: PHP ${{ matrix.php-versions }} Test on ${{ matrix.operating-system }}
-        runs-on: ubuntu-20.04
+        runs-on: ubuntu-18.04
 
         strategy:
             fail-fast: false