Does the Apple Watch updated to the last version pair to iPhone on iOS 14
Inquire
I should, but some who tried have visibly got serious problems:
https://developer.apple.com/forums/thread/682815.
You'd better double check by contacting Apple Support (Contact Us link at the bottom of this page).
You will need to update your phone to iOS 15 if your watch is running watchOS 8 (as it will be if you just bought a Series 7 Apple Watch, for example).