osTicket/osTicket-1.7 — pull request #748 by protich (2013-09-29 14:11:04+00:00)
Title: Message id tracking revisited

Ticket number matching is the last-resort when email header references matching fails. Without forced email check - a third party could in theory inject responses or messages by spoofing the headers and using random ticket numbers on the subject line.

The check will also help force staff replies to be limited to positive message-id match.