diff --git a/.github/workflows/phpunit-tests.yml b/.github/workflows/phpunit-tests.yml
index 36d9d8e6f1439..0c8598584a612 100644
--- a/.github/workflows/phpunit-tests.yml
+++ b/.github/workflows/phpunit-tests.yml
@@ -45,7 +45,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ ubuntu-latest ]
-        php: [ '5.3', '5.4', '5.5' ]
+        php: [ '5.3' ]
         split_slow: [ false, true ]
         multisite: [ false, true ]
         memcached: [ false ]