JensK
The big question is how come these settings weren't updates correctly?
Most/all user settings in sme are not changed when updates occur.
The default installation from CD does not enable RBL or spam filtering, the admin user needs to make these changes either by command line (for RBL) or via server manager (for spam filter).
That's the way it is, some people do not want these enabled as default, so the developers felt it wiser to leave them disabled.
The real issue (& probably the most important issue from the developers point of view), is whether the upgrade process directly caused your problems. If so, that implies there is something wrong with the upgrade process & it needs fixing.
As your settings (after the upgrade) do not appear to be any different than a default install, then any issues you have may just be due to coincidental increased spammer activity and your "lack of knowledge/ignorance" of required settings.
Of course if you still have problems after tweaking your system as suggested, then you should report to the bugtracker. There are a number of spam type bugs, some relating to systems that have been upgraded from older sme7 versions and those that have had spam filter additions, so search & read the bugtracker first.