Just curious was there any significant changes in LDAP between 3.0.0 and 3.1. Tried to do an upgrade last night (2 machines 1 dedicated spam filter) on the spam filter machine and it seemed everything went ok. But when i tried to email myself i was getting bouncebacks. A manual telnet to port 25 indicated it was accepting the email address as being valid and showed the message being queued however mins later i was getting bounce backs. The main mail store/ldap was on the other machine which the filter machine looks at that ldap. Even a full reinstalled of 3.1 from scratch was giving me the problem. However going back to 3.0.0 fixed the issue.
Did not upgrade second machine (ldap). Like to get delivery working first for trouble shooting purposes.