Courier IMAP/POP3
=================

If you're using only Courier IMAP, it's possible to do a perfectly transparent
Dovecot migration. If you're using Courier POP3 and you have users who keep
mail in the server, you may have problems keeping the POP3 UIDLs unchanged.

Courier v0.43 and later to Dovecot v1.1+
----------------------------------------

courier-dovecot-migrate.pl
[http://www.dovecot.org/tools/courier-dovecot-migrate.pl] does a perfect
migration from Courier IMAP and POP3, preserving IMAP UIDs and POP3 UIDLs. It
reads Courier's 'courierimapuiddb' and 'courierpop3dsizelist' files and
produces 'dovecot-uidlist' file from it. Note that it works properly only with
Dovecot v1.1 and later, see the next section for v1.0.

Before doing the actual conversion you can run the script and see if it
complains about any errors and such, for example:

---%<-------------------------------------------------------------------------
# ./courier-dovecot-migrate.pl --to-dovecot --recursive /home
Finding maildirs under /home
/home/user/Maildir/dovecot-uidlist already exists, not overwritten
/home/user/Maildir2: No imap/pop3 uidlist files
Total: 69 mailboxes / 6 users
       0 errors
No actual conversion done, use --convert parameter
---%<-------------------------------------------------------------------------

The actual conversion can be done for all users at once by running the script
with '--convert --recursive' parameters. Make sure the conversion worked by
checking that 'dovecot-uidlist' files were created to all maildirs (including
to subfolders).

You can also convert each user as they log in for the first time, using
<PostLoginScripting.txt> with a script something like:

---%<-------------------------------------------------------------------------
#!/bin/sh
# WARNING: Be sure to use mail_drop_priv_before_exec=yes,
# otherwise the files are created as root!

courier-dovecot-migrate.pl --quiet --to-dovecot --convert ~/Maildir
# This is for imap, create a similar script for pop3 too
exec /usr/local/libexec/dovecot/imap
---%<-------------------------------------------------------------------------

Courier v0.43 and later to Dovecot v1.0
---------------------------------------

An older version of the courier-dovecot-migrate-1.0.pl
[http://www.dovecot.org/tools/courier-dovecot-migrate-1.0.pl] attempts to do as
good migration from Courier as possible for Dovecot v1.0. If you're using only
IMAP, the migration will be perfect, but with POP3 the IMAP UIDs or POP3 UIDLs
may have to be changed.

Before the actual conversion, you can check how well it can be done:

---%<-------------------------------------------------------------------------
# ./courier-dovecot-migrate-1.0.pl --recursive /home
Finding maildirs under /home
/home/tss/Maildir/courierpop3dsizelist: 2 / 2956 needs changing
/home/tss/Maildir/courierimapuiddb: 2956 / 2957 needs changing

Total: 2 POP3 changes, 2956 IMAP changes, 0 errors
---%<-------------------------------------------------------------------------

This means that 2 POP3 UIDLs need to be changed (clients will download them as
duplicates) and only one IMAP UID can be converted without changing it.
Changing IMAP UIDs isn't as bad, it will only cause a somewhat heavier load to
your mail server when the IMAP clients begin downloading the old mails again.

Dovecot configuration
---------------------

Courier by default uses "INBOX." as the IMAP namespace for private mailboxes.
If you want a transparent migration, you'll need to configure Dovecot to use a
namespace with "INBOX." prefix as well.

---%<-------------------------------------------------------------------------
protocol pop3 {
  # If you used the v1.1+ migration script, you probably should keep using
  # the default pop3_uidl_format (%08Xu%08Xv) instead of changing this.
  pop3_uidl_format = UID%u-%v
}

mail_location = maildir:~/Maildir

namespace private {
  prefix = INBOX.
  inbox = yes
}
---%<-------------------------------------------------------------------------

Manual conversion
-----------------

 * Courier's 'courierimapsubscribed' file is compatible with Dovecot's
   'subscriptions' file, but you need to remove the "INBOX." prefixes from the
   mailboxes.
 * Courier's 'courierimapuiddb' file is compatible with Dovecot's
   'dovecot-uidlist' file, just rename it.
 * Courier's message flags are compatible with Dovecot (as they are specified
   by the Maildir specification)
 * Courier's message keywords implementation isn't Dovecot compatible. There
   doesn't exist a simple way to convert the keywords manually.

Older Courier POP3 versions to Dovecot v1.0
-------------------------------------------

With the v1.1+ migration script you can use any pop3_uidl_format, because the
UIDLs are stored directly in the dovecot-uidlist file.

Courier version 0:
  ---%<-----------------------------------------------------------------------
  # Courier version 0 (using maildir filenames)
  pop3_uidl_format = %f
  ---%<-----------------------------------------------------------------------

Courier version 1:
  ---%<-----------------------------------------------------------------------
  # Courier version 1 (UID)
  pop3_uidl_format = %u
  ---%<-----------------------------------------------------------------------

Courier version 2 and early Courier version 3:
  ---%<-----------------------------------------------------------------------
  # Courier version 2 (UIDVALIDITY and UID - you most likely want this)
  pop3_uidl_format = %v-%u
  ---%<-----------------------------------------------------------------------

Dovecot v1.0, ManageSieve server and namespaces
-----------------------------------------------

Dovecot v1.0's <deliver> [LDA.txt] ignores namespaces, so <Sieve>
[LDA.Sieve.txt] scripts shouldn't include namespace prefixes in *fileinto*
destinations. If Sieve scripts are generated by some tool it probably includes
these prefixes. If the script is uploaded via<ManageSieve server>
[ManageSieve.txt] you can kludge around this problem by using the script below.
Dovecot v1.1's deliver doesn't ignore namespaces and this must not be done with
it.

First modify managesieve configuration in dovecot.conf to execute your script
instead:

---%<-------------------------------------------------------------------------
protocol managesieve {
  ..
  mail_executable = /usr/libexec/dovecot/managesieve-nsfix.sh
}
---%<-------------------------------------------------------------------------

Then create the '/usr/libexec/dovecot/managesieve-nsfix.sh' script:

---%<-------------------------------------------------------------------------
#!/bin/bash
# by Allan GooD: allan.cassaro (at) gmail.com
export PATH="/bin:/usr/bin"

CONF="/etc/dovecot/dovecot.conf"

/usr/libexec/dovecot/managesieve
ERR=$?

NAMESPACE="`grep prefix $CONF | head -n1 | awk '{print $3}'`"

if [ -h "${HOME}/.dovecot.sieve" ] && [ "${NAMESPACE}" ]; then
  FILE="${HOME}/`ls -l ${HOME}/.dovecot.sieve | awk '{print $11}'`"
  SIEVE="`sed s/${NAMESPACE}/''/g $FILE`"
  echo "${SIEVE}" > ${FILE}
fi

exit $ERR
---%<-------------------------------------------------------------------------

Note that this script removes everything from the script matching the namespace
prefix, so in some rare cases it might break the script.

(This file was created from the wiki on 2009-01-05 04:42)
