watchOS 5.0 (build 16R364) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2018-09-12T19:18:59Z. The update package is 768.41 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: 256d0543f0b1963b4e145219c084238e69898fe8.zip.