diff --git a/.travis.yml b/.travis.yml
index 2af5cf5f..84e0442f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,7 +1,10 @@
 language: php
 php:
+  - 5.6
+  - 5.5
   - 5.4
   - 5.3
+  - hhvm
 before_script:
   - composer install --dev --prefer-source --no-interaction
 script: