watchOS 5.0 (build 16R5340g) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2018-08-06T17:11:52Z. The update package is 490.43 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: 88ce727377715885d5550d729641b25b77a01ea6.zip.