diff --git a/composer.json b/composer.json
index d563fa2b9524..ba72f66cabb0 100644
--- a/composer.json
+++ b/composer.json
@@ -28,7 +28,7 @@
         "paragonie/random_compat": "~1.4|~2.0",
         "psy/psysh": "0.7.*|0.8.*",
         "ramsey/uuid": "~3.0",
-        "swiftmailer/swiftmailer": "~5.1",
+        "swiftmailer/swiftmailer": "~5.4",
         "symfony/console": "3.1.*",
         "symfony/debug": "3.1.*",
         "symfony/finder": "3.1.*",