watchOS 5.0 (build 16R5363a) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2018-08-31T17:15:37Z. The update package is 620.19 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: cb11596b82d683089ea67ca7f3f6ef168c870557.zip.