Why was it implemented with UIApplicationMain wrapped with a @autorelease in the first place then? Also, does it mean that the UI thread is no longer wrapped with an @autorelease pool? Shouldn't Cocoa framework now trigger errors if the autorelease method is used inside of UI thread?

Does it mean, that we cannot reliably say this features will hold in future releases, and this is rather implementation-dependent detail?

Please read the question carefully. I'm not asking how to check for conformance, it's literally in the sample code.