That's great - thanks for the information. That is really helpful and makes good sense.
On that basis then, all that is needed in each case is a check of whether the various arguments to be passed to the mail procs are integer keys or not. If so, look up the email address.
I guess in an ideal world, the mail procs would sort this out for themselves based on whatever value is passed, but the problem is as you say, that the signature of the call itself has changed.
Is it possible for a non-registered user to submit a bug?
I will modify my copy of the files relevant to the bug-tracker notifications and inevitably the mail tracking package but need to work out how to capture that and feed it back to the codebase. I presume I can checkout a single file and then commit it back in isolation?
On that score, does anyone know who the maintainer is for mail-tracking?