Apple has released the watchOS 5.1 update yesterday, but has now stopped its distribution after several reports surfaced of Apple Watches getting bricked upon installing the refresh. This is a serious issue because, unlike the case of iPhones, the Apple Watch can’t be plugged in and accessed from a computer for troubleshooting, with the only option being contacting Apple Support.
On the bright side, if there’s any to this story, is that the issue seems to only be affecting the new Apple Watch Series 4 models. watchOS 5.1 was released together with iOS 12.1 and brings support for new emoji, group FaceTime audio, and a new color full screen watch face.
If you managed to download the watchOS 5.1 update yesterday before it was pulled, stay away from applying the update to your Apple Watch. It will possibly render your device unusable. Wait for Apple to re-release the update before doing anything.