title: Mailsystem Failure Delivery - Custom subject
body: <p>When a mail is bounced it has a standard subject.
  Is it possible to change with a custom subject or the subject which we gave or with a dynamic subject?
  I am building a simple system in php to count all send and not sent mails with the help of bounced mails.
  So i need to parse the body of the bounced mail to find the email address to which the mail was not sent.
  If there could be any other less overhead option then that could be nice. We can reduce the processing time to parse.</p>