My forum is a continuous upgrade from version 1.x
About 6 months ago (or so) I upgraded from 3.0 to 3.2 (3.3) (3.3 came out at exactly that time, and I did a 3.2 > 3.3 upgrade)
I managed to get through most of the teething problems.
Because of the private nature of my forums, I control all access to the forums via a usergroup. New users must request membership to that usergroup, and I review and approve their request.
In version 3.0, every time someone requested entry to that group, I got an email. In 3.3, I do not. I have spent some time browsing through the ACP to see where I can turn that back on, but so far, no luck.