diff --git a/build/composer.json b/build/composer.json
index 64b224677..e2622dc7c 100644
--- a/build/composer.json
+++ b/build/composer.json
@@ -11,7 +11,7 @@
         "phing/phing": "^2.16",
         "phploc/phploc": "^4.0",
         "phpmd/phpmd": "^2.6",
-        "phpunit/phpunit": "^5.7",
+        "phpunit/phpunit": "^6.5",
         "sebastian/phpcpd": "^3.0",
         "squizlabs/php_codesniffer": "^2.9"
     },