The watch app in iOS 9 won't let you set up a watch running OS3. HOWEVER, if you don't reset the watch before going back to iOS 9, the watch will still do all the things it can via cloud connection so long as youre near a trusted wifi network; I.e. Siri, iMessage, FaceTime audio. It will still track your fitness, but without the Phone that data has nowhere to go.Is that true? i thought I read from someone here that some features were not available (health among them) but that basic features (time keeping, notifications) still worked? I could just be mis-remembering, though.