iPhone 6 Plus iOS 15.7.3 update

The iPhone 6 Plus cannot run any version of iOS newer than iOS 12, the current version of which is, as I write, iOS 12.5.7.

About iOS 12 Updates - Apple Support

The iPhone 6 Plus hardware is not powerful enough to run anything newer.

With iOS 16, Apple ceased software support for the 6S, 6S Plus, SE 2016, 7, and 7 Plus.

iPhones 8 (2017) or newer can run iOS 16. 

I want to download google chat

How can I download it

Ask Google

With iOS 16, Apple ceased software support for the 6S, 6S Plus, SE 2016, 7, and 7 Plus.

Really? Why was a new iOS 15 update........iOS 15.7.3......available months after iOS 16 was introduced?