diff --git a/ApplicationConfig/Providers/RootInfo.php b/ApplicationConfig/Providers/RootInfo.php
index 61578967e..71ab49ffa 100644
--- a/ApplicationConfig/Providers/RootInfo.php
+++ b/ApplicationConfig/Providers/RootInfo.php
@@ -13,9 +13,11 @@ class RootInfo implements Provider
     /** @var \Symfony\Component\HttpFoundation\RequestStack */
     private $requestStack;
 
-    /** @var \Symfony\Component\Templating\Asset\PackageInterface */
+    /** @var \Symfony\Bundle\FrameworkBundle\Templating\Helper\AssetsHelper */
     private $assetsHelper;
 
+    private $externalAssetsDirectory;
+
     public function __construct(RequestStack $requestStack, AssetsHelper $assetsHelper, $externalAssetsDirectory)
     {
         $this->requestStack = $requestStack;
diff --git a/composer.json b/composer.json
index f4638be92..a608e2201 100644
--- a/composer.json
+++ b/composer.json
@@ -17,6 +17,7 @@
         "jms/translation-bundle": "^1.3"
     },
     "require-dev": {
+        "symfony/symfony": "~2.8.0",
         "phpunit/phpunit": "~4.7",
         "matthiasnoback/symfony-dependency-injection-test": "^0.7",
         "mockery/mockery": "^0.9.5"