watchOS 6.0 (build 17R5575a) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm, LTE), released on 2019-08-27T17:32:03Z. The update package is 710.43 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: 858ecf27cb9956d6b4bf79e72dbb2361bb156685.zip.