diff --git a/.travis.yml b/.travis.yml
index 1abb9e0..cfd4c49 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,7 +3,7 @@ language: ruby
 rvm:
   - 1.9.3
   - 2.0.0
-  - 2.1
+  - 2.1.8
   - 2.2.4
   - 2.3.0
   - ruby-head