[Dovecot] Staged migration from mbox to maildir

[Stewart Dean]

So much changes in this migration that the ideal way to do it would be 
to begin with a few users or a department, then migrate the users 
affinity group by affinity group: first an institute or so, then the 
faculty, then the staff, then the students, moving to bigger and bigger 
groupings as the bugs work out of the migration and the move becomes 
more assured.

We use sendmail and procmail.  There's no problem there, as the 
~./procmailrc can be changed to over-ride the mbox default until all 
groups are done and it become the default.
The problem comes with IMAP.  While dovecot can tell if a folder is mbox 
or maildir, it has to be pointed to the right place (by namespace 
definitions in the client, IIRC), and the default of putting the inbox 
under ~/mail is one I'd like to embrace for various reason...but given 
that that means moved inbox folders and *that* means either making a 
global change (there goes staged migration) OR changing the namespace 
definitions on each PC.  I can get to the early few and change the 
namespaces definition, but there doesn't appear to any equivalent 
(enlighten me, if I'm missing something) to ~/.procmailrc for imap, so 
that I don't have to get on the client machine.

Is this correct or am I (hopefully) wrong and there *is* a way to change 
things on the server that allows for staged migration?  Oh, I would so 
like to be wrong!
IMAP should have an rc file.............
-- 
"Eppur si muove." (But Still it moves) Galileo, leaving the Inquisition, 
after buckling under the threat of torture and excommunication and 
recanting from his proof that the heavens do not revolve around the 
earth --
Stewart Dean, Unix System Admin, Henderson Computer Center, Bard 
College, Annandale, New York 12504 sdean at bard.edu voice: 845-758-7475, 
fax: 845-758-7035