Yesterday, Apple was focusing on announcing a number of device updates, including a new MacBook Air with Retina Display, a long delayed Mac Mini update and new 11-inch and 12.9-inch variants of iPad Pro. But there are software updates we're talking about today, and especially the slim release of watchOS 5.1 for Apple's smartwatches.
Something went very badly with watchOS 5.1 to the point where trying to update an Apple Watch Series 4 could mess it up. Like 9to5Mac reports, the problem seems to be limited to Series 4 devices, but it is serious that Apple pulled the update. If you managed to download it, the advice is not currently trying to update your time, as you may be left with a dead clock.
No explanation has come from Apple about what happened, but you know watchOS 5.1
WatchOS 5.0 was released on September 17th and introduced a number of enhancements to Siri and Notifications while adding a Walkie Talkie and Podcast app, new forms of training, and is generally smarter to detect what activity you are doing. The update to 5.1 yesterday was supposed to introduce 70+ new emoji also included in iOS 12.1, but obviously, wait for Apple to see what went wrong.