We're considering a move from Courier to Dovecot.  So far, looks like

it's not too bad, but the most challenging obstacle is what to do about our local delivery.  Factors:

1. we use a lot of maildrop "features" that are impossible in sieve

without piping to an external program (would rather not re-write our working maildrop scripts in another language)

2. would love to try dbox

3. we use IMAP/Maildir++ quotas (looks like with a little finesse it's possible to get maildrop and dovecot to play nice on this account, yes?)

I saw it suggested to just call LDA from maildrop for any maildrop "to" commands (hmmm, what about "cc"?) here:

http://article.gmane.org/gmane.mail.imap.dovecot/56120

How much overhead will this take?  Would it be possible or advisable to use LMTP instead if that would help?  Is this idea just too crazy?

Oh, doing this would also have benefit of updating dovecot indexes upon delivery, and we could ignore point 3 about the quotas and just let dovecot handle deliver time quotas too right?  (remove quota support from maildrop)

Also saw a suggestion to do it a little different:

http://article.gmane.org/gmane.mail.imap.dovecot/44897

So maildrop

to "| foo" to "! foo@bar.com" cc "| foo" cc "! foo@bar.com"

are left as is

then

to "<mailbox name>"

is replaced with either:

xfilter "/usr/lib/dovecot/dovecot-lda -m <mailbox name>" to "| /dev/null"

or just:

to "| /usr/lib/dovecot/dovecot-lda -m <mailbox name>"

and

cc "<mailbox name>"

is replaced with either:

xfilter "/usr/lib/dovecot/dovecot-lda -m <mailbox name>"

or just:

cc "| /usr/lib/dovecot/dovecot-lda -m <mailbox name>"

and the default end-of-script (INBOX) delivery for maildrop (an assumed "to 'INBOX'" command) can probably be replaced with one or the other of:

xfilter "/usr/lib/dovecot/dovecot-lda" to "| /dev/null"

or:

to "| /usr/lib/dovecot/dovecot-lda"

Does any of this make sense?  I wonder how it will look to the MTA (postfix here) when delivery fails.  It's also creating duplicate user lookups for the two delivery agents which isn't great.

Maybe it'd be better to consider learning how to re-write our needed maildrop scripts as shell scripts (maildrop is close enough to bash I guess) and making sieve pipe out to them?