FWIW folks, I have upgraded my iPhone to iOS11. And guess what?
It still syncs, backs up, and performs all the functions that I normally use with
12.6.2. I can still download apps in the iTunes App Store in 12.6.2 and then
download them to my iPhone. The the app management functions of moving
between screens and groups still sync to changes to the iPhone.
How long this will still continue is to be determined. Perhaps, iTunes 12.7
is required for some particular features or maybe some easier use with the
Files app in iOS and other "stuff" (part of drag and drop stuff?). Although,
don't know if a restore would work??
So for the moment, I am still content.
PS. Still have to get use to double clicking the Home button
on the phone to bring up app switching again. Really liked the
hard press and slide from edge.