watchOS 6.0 (build 17R5566a) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2019-08-15T17:17:13Z. The update package is 687.04 MB. This is a delta (partial) update that requires 5.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 4523c829fa95819bc5483f0441164b06776c68c2.zip.