iPhone 6 maximum iOS

You don’t have an iPhone 6 if it has 15.7.3. The highest version for an iPhone 6 is 12.5.7.

A iPhone 6S can be updated to 15.8.1. I would strongly urge you to update to that version, because it fixes over 40 security vulnerabilities found in earlier versions.

If your device is running any version of iOS higher than 12.5.7, it cannot be an iPhone 6.

Please check the model number at: Settings - General - About - Model = ???

wayde228 wrote:

I HAVE an iPhone 6, and your answer contradicts itself. If I could, I would send you a picture from the settings screen. Jeees!

He's right... check out the link I provided above Supported iPhone models - Apple Support (CA)

In version IOS 12, iPhone 6 is compatible with. Any version after that is iPhone 6s. If you are running the version you have, then you are iPhone 6s.

Input the versions yourself and have a look. :)

His answer does not contradict itself and you do not have an iPhone 6 if you're running iOS 15.7.3.

Found this on Is my iPhone an iPhone 6 or 6s? ****

If you’re wondering whether your phone is an iPhone 6 or 6s, the easiest way to tell is to look at the back of the phone and see if it has the “S” logo at the bottom of the casing. If you don’t see it, then you’re probably using an iPhone 6.

[Edited by Moderator]

Go into the software settings and don't allow auto updates/installs.

iPhone models compatible with iOS 15.5 - Apple Support (CA)