diff --git a/src/Bridges/MailDI/MailExtension.php b/src/Bridges/MailDI/MailExtension.php
index 53c1004..887fd35 100644
--- a/src/Bridges/MailDI/MailExtension.php
+++ b/src/Bridges/MailDI/MailExtension.php
@@ -27,6 +27,7 @@ class MailExtension extends Nette\DI\CompilerExtension
 		'timeout' => null,
 		'context' => null,
 		'clientHost' => null,
+		'persistent' => false,
 	];