watchOS 6.0 (build 17R5566a) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2019-08-15T17:18:41Z. The update package is 687.56 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: e9f8f04dad97d2b9005190bbcc23ed19337893c4.zip.