watchOS 6.0 (build 17R5521e) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm, LTE), released on 2019-07-02T18:11:03Z. The update package is 687.75 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: 55437c375e56ae01c2f565d29161182f2e6b02bc.zip.