I want to upgrade my phone to the latest version
Update app to the version latest one
Build 'hardware' version (iPhone identification?) is required to know
which iOS 'software' Version that unit could be able to use or get.
You have that, nobody in these voluntary ASC discussions does.
The iPhone if set up to update, can tell you which it has, or needs.
Open-ended no details research on your side, makes this a guess.