TYPO3 Core

With transport_smtp_encrypt = tls set for STARTTLS SMTP connections,
TYPO3 v10 will cast transport_smtp_encrypt to bool.
That boolean is passed to symfony mailer which interprets TLS = true as SSL (ssl://) connection.

That results in the following error when sending a mail:

Could not deliver mail
Please verify $GLOBALS['TYPO3_CONF_VARS']['MAIL'][*] settings are valid. Error message: Connection could not be established with host "ssl://mail.your-server.de:587": stream_socket_client(): SSL operation failed with code 1. OpenSSL Error messages: error:1408F10B:SSL routines:ssl3_get_record:wrong version number.

To use TLS (STARTTLS) TLS = false would need to be passed to Symfony\Component\Mailer\Transport\Smtp\EsmtpTransport.

Should TYPO3 provide a smooth migration to set transport_smtp_encrypt=tls to TLS=false?