http://wiki.dovecot.org/Migration/MailFormat shows a bunch of scripts, one of them claims to preserve UIDs.
Does anyone here have direct successful experience with this? I only asked about this because a comment on that same page says, "None of the solutions described below preserve the message UIDs."
(Some of my users have > 1 GB of email, so any UID disruption would likely be seriously annoying to them.)
