watchOS 5.0 (build 16R5313d) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2018-07-03T17:11:19Z. The update package is 624.9 MB. This is a delta (partial) update that requires 4.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 2b580c358fd568eca46c455844212bfa3ba25650.zip.