watchOS 5.0 (build 16R5283r) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2018-06-11T17:07:06Z. The update package is 602.93 MB. This is a delta (partial) update that requires 4.3.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 859476c8204fc48195da9dd250e4626c111ab481.zip.