There is a new case, but I understand that the dimensions are the same. Just some ports got moved and the holes don't line up.
Yes, Jason's right. Same mounting holes and overall board XY dimensions, but some ports have been moved around. It's possible to use the old enclosures and cut/enlarge some holes, but better to use the new enclosures.
From reading on one of the other ( and many) forums when you buy the 2.5 it comes with a case. I hope so because I did not order one and I would have.
Right now, when you order APM 2.5 you get a credit for a free case when they become available (in about a month).