iOS update

The iPhone 6 Plus cannot be upgraded past iOS 12, the last version of which was iOS 12.5.7 as the hardware is too old to run newer versions.

If you need to run a later version of iOS, you will need to purchase a newer device.

The iPhone 6 plus can only be updated to iOS 12.5.7. It lacks components needed to run newer updates.

Please take the time to read the replies you have already received. The iPhone 6 cannot be updated past iOS 12.5.7.