I got an iPhone 5 with iOS 7.1.2 should I upgrade to iOS 10.0.2? Or maybe upgrade to some other firmware version like 8.4.1? I looked up some apps on the App Store and it looks like most apps require iOS 8.0 and later. What iOS version is required for most of the apps on the Cydia App Store? What are some of the pros/cons for keeping 7.1.2 and upgrading to a newer firmware? Maybe faster performance and better battery life on the old firmware?