Engines 1.2
For the full list of changes, check out the CHANGELOG and particularly the UPGRADING notes - if you're an old-style "engine" developer and you want to rejoin the Light side of the Force, you're going to need to make some small changes to your code.
1.1系のEnginesに対応したプラグインはUPGRADING noteを読んだら1.2に対応できるらしい。