watchOS 5.0 (build 16R5334f) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2018-07-30T17:10:21Z. The update package is 668.48 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: b330a49b53154c5c1dfd173a389ed0b3d473ae57.zip.