I was wondering if programming languages and frameworks get updated in small increments or are they just x.0 releases? And if they do how do you keep up on all the changes in every update? I am specifically interested in Objective-C and Cocoa and CocoaTouch.
I'm learning from books and online PDF's etc, but often they are at best a few years old. I just would like to know if there have been any changes etc. that should concern me and even if not, inevitably there will be, so where can I look out for them?