diff --git a/composer.json b/composer.json
index 4f7ad2915..70f5fc99c 100644
--- a/composer.json
+++ b/composer.json
@@ -88,7 +88,7 @@
         "doctrine/doctrine-fixtures-bundle": "~2.2",
         "doctrine/data-fixtures": "~1.1.1",
         "sensio/generator-bundle": "^3.0",
-        "phpunit/phpunit": "~5.0",
+        "phpunit/phpunit": "~4.0",
         "symfony/phpunit-bridge": "^3.0",
         "friendsofphp/php-cs-fixer": "~1.9",
         "m6web/redis-mock": "^2.0"
@@ -125,7 +125,10 @@
         "psr-4": { "Tests\\": "tests/" }
     },
     "config": {
-        "bin-dir": "bin"
+        "bin-dir": "bin",
+        "platform": {
+            "php": "5.5.9"
+        }
     },
     "minimum-stability": "dev",
     "prefer-stable": true