If the mobile phone version is also iOS 10 system, it's okay to upgrade it, but if it's iOS9 system, don't upgrade it. The effect of 6P band 10 is generally outstanding, and various bugs of iOS 10.3.3 system have not been fixed, such as horizontal screen bug, crash bug and frame drop, which are more serious than 10.2. 1.
In short, upgrading from 6p to iOS9 is almost enough. Going up, you will face the flashback of various applications, and the experience will be greatly reduced.