watchOS 6.0 (build 17R5566a) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm, LTE), released on 2019-08-15T17:19:08Z. The update package is 709.88 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: 14e8dfc623b9a1d45b65e4663da1ab8e42432a44.zip.