watchOS 5.0 (build 16R364) is an official Apple over-the-air update for the Apple Watch Series 3 (42mm, LTE), released on 2018-09-12T19:19:08Z. The update package is 774.01 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: 83014e28c50a6e139fda4b2045a3f46311f632dc.zip.