diff --git a/composer.json b/composer.json
index 50ae76f..69e24a9 100644
--- a/composer.json
+++ b/composer.json
@@ -16,6 +16,6 @@
     "psr-4": { "Xenzilla\\Graph\\": "test/" }
   },
   "require-dev": {
-    "phpunit/phpunit": "4.5.*"
+    "phpunit/phpunit": "4.8.*"
   }
 }
\ No newline at end of file