strtolower(): Passing null to parameter #1 ($string) of type string is deprecated

[Salem-Matloob-Al-Twami]

• Laravel Version: 8.64.0
• PHP Version: 8.1.0

Description:

strtolower(): Passing null to parameter #1 ($string) of type string is deprecated.

To my humbling understanding,

This issue is there because we create an object of Swift_SmtpTransport with $transport = new SmtpTransport( $config['host'], $config['port'] ); on MailManage.php and on the constructor of Swift_SmtpTransport public function __construct($host = 'localhost', $port = 25, $encryption = null) and the default value of $encryption would be null and we call $this->setEncryption($encryption); on it!!
I had to downgrade my PHP to 8.0 to avoid this issue.

Is there any other fix to it?

Thank you

[driesvints]

Please upgrade to Swiftmailer 6.3.0 which provides PHP 8.1 support.