diff --git a/.travis.yml b/.travis.yml
index f0f5793..02ed547 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,6 +4,8 @@ notifications:
 language: node_js
 
 node_js:
+  - '6'
+  - '4'
   - '0.10'
 
 before_install: