diff --git a/.travis.yml b/.travis.yml
index 839426e..c1c2d34 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -20,12 +20,14 @@ env:
     # Supply more than one RACKET_VERSION (as in the example below) to
     # create a Travis-CI build matrix to test against multiple Racket
     # versions.
-    - RACKET_VERSION=6.0
-    - RACKET_VERSION=6.1
-    - RACKET_VERSION=6.1.1
-    - RACKET_VERSION=6.2
-    - RACKET_VERSION=6.3
-    - RACKET_VERSION=6.4
+    #- RACKET_VERSION=6.0
+    #- RACKET_VERSION=6.1
+    #- RACKET_VERSION=6.1.1
+    #- RACKET_VERSION=6.2
+    #- RACKET_VERSION=6.3
+    #- RACKET_VERSION=6.4
+    #- RACKET_VERSION=6.5
+    - RACKET_VERSION=6.6
     - RACKET_VERSION=HEAD
 
 matrix: