The most tested incremental update in the history of iOS is ready to download an install. I haven't heard enough from people with older devices to give you s definitive answer, but if you are already on iOS 9.2.1, there is probably no good reason not to upgrade. Those of you still on iOS 8, as always, maybe wait a bit and we'l see what the pioneers report from the front. Certainly, if you have a 6S or a 6, go ahead and upgrade to 9.3 and enjoy the new NightShift feature whi