Help/Support Restoring Iphone 7

[BipoIarBear 62 iPhone 12 Pro Max 15.0]

Hey everyone. I have a quick question...

I currently have an iPhone 7 running on the IOS 11.0.3 but I am wanting to go back to IOS 10.2 or 10.3

I have on my ITunes 2 back-ups from my old IPhone 6 Plus back in August, one is a 10.3 backup and one is a 10.3.1

I have tried to restore one of those backups trying to get back to the old IOS but every time it starts restoring it comes up with an error saying "can't restore because phone disconnected" 
I am wondering if this is because I am attempting to go back to an old IOS or if it's something else...

I am wondering if there is any way possible to go back to one of these old backups. 

Thanks
 

[K_K 167.6k iPhone 13 Pro Max 15.1]

Nope there is endless info about this on the internet. Going forward is easy going back to an old IOS is not going to happen

[BipoIarBear 62 iPhone 12 Pro Max 15.0]

4 minutes ago, K_K said:

Nope there is endless info about this on the internet. Going forward is easy going back to an old IOS is not going to happen

aight. Thanks for the reply.