watchOS 5.0 (build 16R5357a) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2018-08-20T17:09:19Z. The update package is 624.51 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: 330fd675b5d264bb1d72e4a4f3a943e9fdcbf6f9.zip.