I've found another problem after migrating from ISPCP to latest RC.
Looks like there are still old entries in my postfix configuration and I get the following error in my /var/log/mail.log
I see lots of old ISCP references still uncommented in /etc/postfix/main.cf
Aug 13 09:54:12 sosaria postfix/master[2319]: warning: /usr/lib/postfix/smtpd: bad command startup -- throttling
No mail is coming through.