diff --git a/composer.json b/composer.json
index 8723f58d..73008e5d 100644
--- a/composer.json
+++ b/composer.json
@@ -33,7 +33,7 @@
     },
     "require": {
         "php": ">=5.3.3",
-        "phpunit/phpunit": ">=4.8,<=6.0",
+        "phpunit/phpunit": "~4",
         "sebastian/comparator": "~1.0",
         "ext-curl": "*",
         "ext-dom": "*"