From the Dovecot 1.0.1 sample dovecot.conf file:

If you want UIDL compatibility with other POP3 servers, use:

UW's ipop3d : %08Xv%08Xu

...

Note that Outlook 2003 seems to have problems with %v.%u format

which was

Dovecot's default, so if you're building a new server it would be a

good

idea to change this. %08Xu%08Xv should be pretty fail-safe.

NOTE: Nowadays this is required to be set explicitly, since the old

default was bad but it couldn't be changed without breaking existing

installations. %08Xu%08Xv will be the new default, so use it for new

installations.

pop3_uidl_format = %08Xu%08Xv

Notice the *very* small difference in the format between UW's ipop3d and the ones mentioned a little bit below?

I think I just got bitten by this (we moved from UW's ipop3d to Dovecot). Loooots of users just got a lot of new (old) mail again ("Leave mail on server" is a popular setting). Ah well. They really should move to IMAP anyway and now they got some summer reading to do :-)

Is the difference intentional? If so then perhaps this should be more clearly pointed out!

• Peter