diff --git a/composer.json b/composer.json
index 7b8c37b3..d034e3c5 100644
--- a/composer.json
+++ b/composer.json
@@ -32,6 +32,7 @@
         "phpspec/phpspec"          : "2.*",
         "symfony/yaml"             : "2.2.x-dev",
         "symfony/console"          : "2.2.*",
-        "fabpot/php-cs-fixer"      : "0.3.*@dev"
+        "fabpot/php-cs-fixer"      : "0.3.*@dev",
+        "swiftmailer/swiftmailer": "v5.0.0"
     }
 }