watchOS 5.0 (build 16R5357a) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2018-08-20T17:08:51Z. The update package is 620.67 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: 99908ca4a91e2c76138fd8932b5690b87857a4f5.zip.