watchOS 6.0 (build 17R5575a) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2019-08-27T17:29:29Z. The update package is 687.46 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: 7f9e68b2204e3aa8ede2ae80e448a78781011004.zip.