> The iPhone 4 stayed just as good as the day we bought it and my wife didn't bother upgrading until the iPhone 6S. This isn't a typical experience. There's a

> The iPhone 4 stayed just as good as the day we bought it and my wife didn't bother upgrading until the iPhone 6S. This isn't a typical experience. There's a reason that iOS9 is only on 80% of "active devices": people hold off deliberately. There have been many iOS updates since iOS4 that have caused widespread criticism for their effects on older phones.