diff --git a/.github/workflows/continuous-integration.yml b/.github/workflows/continuous-integration.yml
index 3952068..aab9508 100644
--- a/.github/workflows/continuous-integration.yml
+++ b/.github/workflows/continuous-integration.yml
@@ -39,6 +39,7 @@ jobs:
     strategy:
       matrix:
         php-version:
+          - "5.3"
           - "7.0"
           - "7.1"
           - "7.2"