watchOS 5.0 (build 16R5334f) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2018-07-30T17:10:02Z. The update package is 652.55 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: 053942c0cc6fa09a8750019869bb3bb81ca40ac9.zip.