watchOS 6.0 (build 17R5491t) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2019-06-03T19:28:40Z. The update package is 708 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: 88ae6adaf68adf6137088517136d26d4d99b9061.zip.