It looks like iOS 15 causes a continuous crash/boot loop when paired with Series 0, 1 & 2 watches. Unpairing and pairing the watch with iOS 14 resolves the issue. Has anybody here seen this, too? I am seeing it with my original AppleWatch SS and another user is seeing it with Series 1. I am presuming it's a watchOS incompatibility in the comms protocol. I actually worked with Apple Support to have the watch diagnosed and it came out perfect. They sent me a refurb anyway! But the problem persists.