The only problem is that you really want "globally" unique id's.
We've seen a couple of cases with reused uniqueid's (probably our fault
with some of the messy stuff we do at the low level), and it really
stuffs up replication. To get globally unique, you'd have to check every
cyrus.header file of every mailbox if I'm not mistaken?
I don't think they need to be globally unique, just unique per user.
Both replication and the seen DB use per-user unique mailbox IDs.
Ok, for some reason I thought we had problems at one stage with non-globally
unique id's, but I might have been (e.g. most probably was) mistaken.
Rob
