Rather than follow an upgrade path, I painstakingly migrated the mail server configuration from an openSUSE 11.0 server to a fresh install on an openSUSE 11.3 server. Here are the problems I ran into and how I solved them:
Problem: “Permission denied” when postfix/lmtp attempted to connect to /var/lib/imap/socket/lmtp
Solution: run vigr to add user postfix to the mail group.
Problem: imap[14973]: IOERROR: opening /var/lib/imap/user_deny.db: No such file or directory
Solution: it’s okay to ignore this.
Problem: imap[10976]: SQUAT failed to open index file
imap[10976]: SQUAT failed
Solution: you can either ignore this or build SQUAT indexes.
Problem: postfix/smtp[21515]: connect to localhost[::1]:10024: Connection refused
amavis[21058]: (21058-12) (!!)WARN: all primary virus scanners failed, considering backups
Solution: the Problems I found and fixed section of this Virus scanning post seemed to have the answer. All I needed to do was uncomment the ClamAV-clamd lines in /etc/amavisd.conf