watchOS 5.0 (build 16R5349a) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2018-08-13T17:06:40Z. The update package is 505.02 MB. This is a delta (partial) update that requires 4.2.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 1b25cb17bc3ecc7e6e63c6e900ae4a3dddce240c.zip.