watchOS 5.0 (build 16R5313d) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2018-07-03T17:11:04Z. The update package is 591.29 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: 8f7df047a150d1790c02a2565afce11d1f917bd9.zip.