diff --git a/.travis.yml b/.travis.yml
index 5795298..76db03f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1 +1,6 @@
-language: node_js
+language: node_js
+node_js:
+  - "node"
+  - "6"
+  - "5"
+  - "4"