bluetooth compatibility

Ok APPLE ...... What did you do to Bluetooth ????

I bought a new 2018 Honda Civic and Honda says the iPhone 8 works fine with Phone Book, also Call History

They tested using iOS 11.1.1 (158150)

I have the 8 Plus ....... and on YOUR recommendation updated it to 11.2.6

I will add that I previously had an iPhone 6S Plus and it too worked fine, BEFORE I updated to the latest IOS.

What did you do? Why did you do it?

At least give us the OPTION to go back to IOS 11.1.1 -OR- UNDO WHAT YOU DID????

This very well could be my last Apple cell phone !!!!!!!