Migration Strategies?

[Andrew J Caird]

Hello all,
  I'm starting to think about migrating away from UW-IMAP (for the reasons
mentioned a few days ago on this list) to a Cyrus IMAP server that we've
been using for some people for a while.
  It's easy enough to migrate everything except the inbox with mailutil,
and in my (so far) limited testing that works pretty well (see below).
However, how do people deal with migrating the inbox, given that it can
change during the migration?
  More specifically, the email gateway is currently configured to deliver
email to, for example, acaird at uwimap.fccc.edu.  I migrate that inbox, and
before I can switch delivery to acaird at cyrus.fccc.edu, more email comes to
acaird at uwimap.fccc.edu.  Then what?  Alternatively, if I start delivering
email to acaird at cyrus.fccc.edu and then migrate on top of it, does that
cause any problems?  It seems like the second choice is the best one, but
some confirmation from someone who has done or understands this would be
much appreciated.
--
Andrew Caird            andrew.caird at fccc.edu               215.728.4071
Email Administrator                              Fox Chase Cancer Center