IMAP in mutt should be considered beta quality. For the most part it
works well, but it is still not quite as stable or as full-featured
as some of the other drivers. I believe it is now acceptable for
daily use (and that's how I use it now, currently against Cyrus 1.6.24 and
previously against UW-IMAP 4.7 and 2000).

You may still lose some work if you are suddenly disconnected from your
server (but your mailboxes should be fine). Currently accessing the same
IMAP folder with multiple clients is not supported - it may work, but
no guarantees. There are still several non-critical known bugs, see
http://bugs.guug.de/ for the current list.

You may also be disappointed in mutt's handling of very large IMAP mailboxes.
To build the message index mutt must fetch a subset of headers from every
message in the mailbox, which costs time and network traffic linear to the
number of messages in your mailbox.

Nevertheless in general mutt is quite a fast and fully-featured IMAP client.
It tries to be polite to IMAP servers as well, opening few connections and
avoiding needless polls of the server, unlike certain other popular IMAP
clients by certain large corporations :)

Mutt supports almost all official authentication and security protocols for
IMAP, including SSL/TLS, native CRAM-MD5 and GSSAPI routines, and a SASL
plugin which can handle just about everything else.

Please report bugs to mutt-dev@mutt.org and/or brendan@kublai.com. Version,
options, stack-trace and .muttdebug files are a plus.

Brendan Cully <brendan@kublai.com>
20010506
