diff --git a/.travis.yml b/.travis.yml
index a8fae39..42f87d5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -27,6 +27,7 @@ env:
     - RACKET_VERSION=6.1.1
     - RACKET_VERSION=6.2
     - RACKET_VERSION=6.3
+    - RACKET_VERSION=6.4
     - RACKET_VERSION=HEAD
 
 matrix: