watchOS 6.0 (build 17R5571a) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm, LTE), released on 2019-08-21T17:12:17Z. The update package is 711.69 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: 4fea457e30b0e2ac362e2048c1194b21662d2197.zip.