watchOS 5.0 (build 16R5322d) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2018-07-17T17:11:13Z. The update package is 671.64 MB. This is a delta (partial) update that requires 4.3.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 7a25bae2e775ab78618c0368dc9d63f344530a55.zip.