watchOS 5.0 (build 16R364) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2018-09-12T19:19:18Z. The update package is 754.89 MB. This is a delta (partial) update that requires 4.2.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: e51259d46735b66484070634871df95421a1e4fd.zip.