Oh hey! Didn't know someone was still posting here, so sorry for the late response!
Anyways, ZKW-Reborn is not even out yet for iOS (coming in January 2015)
And the reason why the old game didn't work with the new devices is just that it was outdated. Reborn, on the other hand, does work (I own a iPhone 6 myself, and I've been testing it out with this)
Also, there will be a online multiplayer on Reborn! You should go check out some ingame material of it on the facebook/twitter. Just search for "Still Running" and you should find it!