watchOS 5.0 (build 16R364) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2018-09-12T19:18:30Z. The update package is 727.68 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: 70a3caa81aee96d7644b2fe9c7643c2be5e06b7a.zip.