diff --git a/composer.json b/composer.json
index 56262d9..9adb13b 100644
--- a/composer.json
+++ b/composer.json
@@ -24,6 +24,6 @@
     "php":               ">=5.4"
   },
   "require-dev": {
-    "phpunit/phpunit": "4.1.*"
+    "phpunit/phpunit": "~4.8"
   }
 }