iPhone 6(S)/Plus Can I restore an iPhone with iOS version?

[NJDavidD]

For a whole bunch of reasons I'll spare everyone I'm using an iPhone 6S running iOS10. It's perfect for all my needs. I'll be switching to a different brand phone before I'd go to iOS 11 or 12.

I purchased another iPhone 6s (refurbished) to serve as a back-up. It sadly came with iOS11. Is there any way to wipe it completely and load it with the back-up of my existing phone so it reverts to iOS10?

I know Apple doesn't allow downgrades of iOS, but I'm only looking to create an exact back-up. I need help to find out if this is at all possible of if I should give-up looking for a method.

Thanks!

 

[BugeyeSTI]

No, you’re stuck on whatever it came with. You can only update to what Apple is still signing. As of now, that’s 11.4.1 or 12.0.

 

[KrisLord]

You should be able to restore an iOS 10 backup onto an iOS 11 device though.