I want to upgrade my phone to the newest version
I want to upgrade my iPhone version
iPhone 6
Marking your own post as Solved may prevent others from trying to help because they think you have fixed your problem.
An iPhone 6 can't be updated past IOS 12.5.6.
See the article(s) below.
IOS 15 and iPadOS 15 Compatible Devices. *
iOS 14 and iPadOS 14 Compatible Devices. *
iOS 13 and iPadOS are compatible with these devices - Apple Support. *