Movable type upgrade tips: 2.63 to 3.1

This morning, I've been upgrading a personal weblog from Movable Type 2.63 to the latest 3.15 release and thought it would be useful to throw out a couple of notes:

• Because the TypeKey comment system was introduced, you'll need to change various templates to handle comments properly -- look here for hints.
  
• If you've used MT-Blacklist before, the old 1.6 version no longer works because of the extensive changes to MT's comment system. The new version looks great (at least after the first ten minutes of using it).