SIM card?
I'm sending my iphone 6s out for service to get the battery replaced. Can I temporarily reactivate my old iphone 4s with the iphone 6s SIM card?
iPhone 6s, iOS 13
I can't be positive but I don't think it will fit in the 4S.
but if it does you should be able to, but you won't be able to use your backup to restore to that phone.