Fernando has posted a (long overdue) blog update, discussing some of the new features in 11.50.xC2. It's available here.

I've also heard from reliable sources that performance is improved. ;-)

Update: I just thought I'd highlight this point that Fernando made, because it's come round to bite at least one of my customers:

UPDATABLE_SECONDARY
Well, if you already played with IDS 11.50.xC1 and redirected writes you probably know that the parameter to activate the redirected writes was called REDIRECTED_WRITES. Well, the parameter changed it's name. It's now called UPDATABLE_SECONDARY. This is not clearly stated in the release notes (although it's mentioned in the documentation notes). Eric Herbert and I hit this issue, so please be warned if you're going to play with redirected writes.