If you have an older Apple watch and are not going to use it any more is it necessary to unpair the old watch before you pair the new one?
Apple Watch Series 5
It isn't necessary, you can have multiple Apple Watches paired to a single iPhone. However, if you never plan to use the old Apple Watch again, I would advise removing it from your account, along with any older devices which you don't regularly use.
Set up and pair your Apple Watch with iPhone - Apple Support
If you have an older Apple watch and are not going to use it any more is it necessary to unpair the old watch before you pair the new one
