If moving from i OS 10.2.1 to i OS 10.2, you will not be able to restore a 10.2.1 backup to your device on 10.2, so make sure you save anything you want now.
It has been a few days since the release of long-waiting i Phone 6 and i OS 8 at the special event held by Apple.
And as recommended, a large portion of new and existing i Phone users upgraded the old os to latest i OS 8 expected to have better user experience.
This will erase everything off you device and return it to the factory settings.
This tool will eventually allow all 64-bit devices to jailbreak i OS 10.
i Phone 7 and i Phone 7 Plus will be able to use it on i OS 10.0-10.1.1, all other 64-bit devices will be able to use it on i OS 10.0-10.2.
Wan to update i Phone 4 or i Phone 3GS to update latest i OS without updating i Phone baseband to unlock it later using Ultra Sn0w or Gevey SIM? These are the steps to update i Phone 4 or i Phone 3GS to latest i OS firmware without updating the baseband.
Red Sn0w brings the Restore feature to update i Phone i OS without updating the baseband.