UW-IMAP
=======

*WARNING: Badly done migration will cause your IMAP and/or POP3 clients to
re-download all mails. Read <Migration.txt> page first carefully.*

Namespaces
----------

By default UW-IMAP allows access to whole home directory. Since the home
directory may contain many other files as well, many people have chosen to
store their mails in the 'mail/' directory. This usually means that IMAP
clients have been configured to use 'mail/' as their "IMAP namespace prefix"
(the clients use different names for this). This doesn't work with Dovecot,
because Dovecot shows clients only the 'mail/' directory instead of the whole
home directory. So if the IMAP namespace was kept as 'mail/', Dovecot would try
to access the '~/mail/mail/' directory.

There are three ways to fix this:

 1. Remove the IMAP namespace prefix from the clients.
 2. Use namespaces to allow users to keep using the prefix. See "Backwards
    Compatibility" in <Namespaces.txt> for an example configuration.
 3. Configure Dovecot to use home directory ('mail_location =
    mbox:~/:INBOX=/var/mail/%u' and set 'mail_full_filesystem_access=yes'). The
    latter is needed to make '~/mail' and '~user/mail' prefixes work.

A typical mailbox location setting is:

---%<-------------------------------------------------------------------------
mail_location = mbox:~/mail:INBOX=/var/mail/%u
---%<-------------------------------------------------------------------------

~/mbox file
-----------

If a '~/mbox' file exists, UW-IMAP moves all the mails from '/var/mail/user'
into the '~/mbox' file. Currently Dovecot doesn't support this feature. There
are two possibilities to handle this:

 * Move everyone's mails to '~/mbox' and reconfigure your <MDA.txt> to deliver
   new mails there by default.
 * Move the existing mails from '~/mbox' back to '/var/mail/user'.

Subscriptions
-------------

UW-IMAP keeps the list of subscribed mailboxes in '~/.mailboxlist' file, while
Dovecot keeps them in '~/mail/.subscriptions' file. UW-IMAP's subscriptions
also contain the mailboxes with their prefixes, for example:

---%<-------------------------------------------------------------------------
mail/box
~/mail/box2
~user/mail/box3
---%<-------------------------------------------------------------------------

 * If you removed the prefix from the IMAP clients, you'll also have to remove
   these prefixes.
 * You can use <uw2dovecot.sh.txt> script to copy all the users' '.mailboxlist'
   files to '.subscriptions' files (without any prefix removal).
 * It's possible to keep using the '.mailboxlist' filename (as long as it's in
   the same directory) by modifying 'SUBSCRIPTION_FILE_NAME' define in
   'src/lib-storage/index/mbox/mbox-storage.h'

UIDs, flags and keywords
------------------------

Dovecot uses UW-IMAP compatible metadata headers in mboxes, so it's possible to
migrate back and forth without losing any flags, keywords or cause IMAP UIDs to
change.

Locking
-------

UW-IMAP uses dotlock + flock() as the default locking combination, while
Dovecot uses dotlock + fcntl() by default. See <MboxLocking.txt> to determine
what are the correct lock settings for you. To use UW-IMAP compatible locking,
use:

---%<-------------------------------------------------------------------------
mbox_read_locks = flock
mbox_write_locks = dotlock flock
---%<-------------------------------------------------------------------------

DON'T DELETE THIS MESSAGE -- FOLDER INTERNAL DATA
-------------------------------------------------

The first message in a mbox file may contain the subject "DON'T DELETE THIS
MESSAGE -- FOLDER INTERNAL DATA". This system message has information about the
mailbox and its state.

Dovecot v1.0 uses these system messages. Keep them.

Maildir conversion
------------------

If you're planning on migrating to Dovecot, you might also want to switch to
Maildir format as well. However it might be easier to first migrate from
UW-IMAP + mbox to Dovecot + mbox, and only then migrate the users to Maildir
format.

 * http://people.redhat.com/rkeech/maildir-migration.txt describes how to
   migrate from UW-IMAP+mbox to Dovecot v0.99 + Maildir. Note that Dovecot
   v0.99 has slightly different configuration file settings.
 * <Migration.MailFormat.txt> has some migration scripts
 * Here is a tool ([attachment:uw2dovecot.pl]) that will convert mbox, mbx, and
   mix formatted UW-IMAP folders to Maildir/dovecot format.

UW-POP3 (UW-IMAP's POP3 wrapper, ipop3d)
========================================

By default Dovecot generates POP3 UIDLs differently than UW-POP3, which causes
POP3 clients to redownload them as new messages. You can avoid this by setting:

---%<-------------------------------------------------------------------------
pop3_uidl_format = %08Xv%08Xu
---%<-------------------------------------------------------------------------

To utilize the UW login conversion to lowecase, we recommend that you use the
following option:

---%<-------------------------------------------------------------------------
auth_username_format = %Lu
---%<-------------------------------------------------------------------------

You can confirm that the old and the new UIDLs match:

---%<-------------------------------------------------------------------------
telnet localhost 110
user test
pass test
uidl
quit
---%<-------------------------------------------------------------------------

(This file was created from the wiki on 2019-06-19 12:42)
