How to upgrade to ISO’s 14.0
How can I upgrade ISO’s 14.0
iPhone 6 Plus, iOS 12
Question marked as
Marking your own post as best answer may prevent others from trying to help because they think you have fixed your problem.
An iPhone 6 Plus can't be upgraded past IOS 12.5.6.
See the article(s) below which show device compatibility for each IOS version.
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. *