diff --git a/.travis.yml b/.travis.yml
index 53e2d44..d6b41cb 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,9 @@
 language: node_js
 node_js:
+    - 11
     - 10
+    - 9
+
 cache: npm
 script:
   - npm test