watchOS 5.0 (build 16R5363a) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2018-08-31T17:15:17Z. The update package is 609.9 MB. This is a delta (partial) update that requires 4.3.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: a649382cf10d34d8846b9bd0969de4cb85b61e7a.zip.