watchOS 6.0 (build 17R5571a) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2019-08-21T17:11:51Z. The update package is 688.23 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: cae8936be4b0bab0ad880bbd2d854a5d1b0fcfde.zip.