diff --git a/autoload.php.dist b/autoload.php.dist
index cd8bbc54ca..132da3af1c 100644
--- a/autoload.php.dist
+++ b/autoload.php.dist
@@ -18,5 +18,5 @@ AnnotationRegistry::registerFile(__DIR__.'/vendor/doctrine/orm/lib/Doctrine/ORM/
 
 if (is_file(__DIR__.'/vendor/swiftmailer/swiftmailer/lib/classes/Swift.php')) {
     require_once __DIR__.'/vendor/swiftmailer/swiftmailer/lib/classes/Swift.php';
-    Swift::registerAutoload(__DIR__.'/vendor/swiftmailer/swiftmailer/lib/swift_init.php');
+    Swift::registerAutoload(function () { require __DIR__.'/vendor/swiftmailer/swiftmailer/lib/swift_init.php'; });
 }
diff --git a/src/Symfony/Bridge/Swiftmailer/composer.json b/src/Symfony/Bridge/Swiftmailer/composer.json
index 6c1a7cf142..9a10dd5c8b 100644
--- a/src/Symfony/Bridge/Swiftmailer/composer.json
+++ b/src/Symfony/Bridge/Swiftmailer/composer.json
@@ -17,7 +17,7 @@
     ],
     "require": {
         "php": ">=5.3.3",
-        "swiftmailer/swiftmailer": ">=4.1.2,<4.3-dev"
+        "swiftmailer/swiftmailer": ">=4.2.0,<4.3-dev"
     },
     "suggest": {
         "symfony/http-kernel": "self.version"