diff --git a/.travis.yml b/.travis.yml
index cbfc3331d574..251caaf71c44 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,6 +4,7 @@ sudo: true
 
 php:
   - 5.5.9
+  - 5.6.21
 #  - 5.6
 #  - 7.0
 #  - hhvm