Upgraded to MT 3.14. So far nothing has blown up, but let me know if something seems to suddenly work …
UPDATE: Ditto for MT-Blacklist up to 2.04b.
UPDATE: Ditto for MT-Notifier from 2.3.2 to 2.4.1. I think it should work — again, let me know (comment here or e-mail) if you have problems.