How to update my iPhone iOS 12.5 to iOS 15

jman272 wrote:

What you mean I seen somebody that got a 6s and they phone got the new update

Yes, that makes perfect sense, but an iPhone 6 Plus is not the same as an iPhone 6S.

The 6S is one generation newer with twice as much RAM.

The iPhone 6+, released by Apple over seven years ago, cannot be updated beyond iOS 12.5.5.

The iPhone 6 Plus can not be updated further.