Backwards Compatibility Break with PHP 5.6.

My Client is using PHP 5.6 and one of the last updates broke the site.

../download-manager/src/__/Apply.php – line 681
uses ?? which is not compatible with the PHP Version.

Replaceing it with isset() resolved the issue for me.

https://stackoverflow.com/questions/53610622/what-does-double-question-mark-operator-mean-in-php