Most new email servers and control panels now support plus addressing, also called sub addressing, tagged addressing, mail extensions like[email protected]
That gets delivered to [email protected]
and enables to easily create disposable email addresses.
VERP is an acronym that stays for variable envelope return path and enables to set the return path of a message to a plus address to precisely analyze the bounce message and the reply. It is used by many email processors, like inboxes in newsletter systems or CRMs.
WHMCS relies on subject and body to detect a message ticket. By adding a sub address in a return path, it would easily have a more robust way to identify incoming support messages in the support system. An example could be
Support for VERP should be optional.