TYPO3 Core

The migrate mail SMTP encrypt option does not always migrate the setting correctly. This resulted in exceptions sending emails using SMTP from TYPO3.

I had 3 sites (all v10 but < 10.4.2), where the initial value in LocalConfiguration.php was as shown below:

'transport_smtp_encrypt' => ''

With TYPO3 10.4.2, the migrator introduced in #91070 migrated this setting to:

'transport_smtp_encrypt' => true

The is_string check is not fully sufficient here, since under certain conditions (e.g. migrating from V9.5 to 10.4) the value is always a string. Therefore it should also be checked, if the string is empty and if so, transport_smtp_encrypt should be migrated to false