https://techcrunch.com/2018/10/31/apple-pulls-watchos-5-1-update/

PSA: If you’re an Apple Watch owner who is having trouble finding the shiny new WatchOS 5.1 update that Apple just shipped, it isn’t quite ready yet.

Apple initially shipped the update on Tuesday alongside iOS 12.1, but it quickly pulled it hours later following reports that it bricked some Series 4 watches. A number of customers affected took to Reddit and Twitter to warn of the issues, which were first reported by 9to5Mac and caused some watches to be stuck on the loading screen.