watchOS 6.0 (build 17R5566a) is an official Apple over-the-air update for the Apple Watch Series 3 (42mm, LTE), released on 2019-08-15T17:17:40Z. The update package is 740.16 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: 5254d06a3078e0a19c9e68c853307b91701cba6c.zip.