watchOS 6.0 (build 17R5575a) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2019-08-27T17:29:58Z. The update package is 737.18 MB. This is a delta (partial) update that requires 5.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 414322e3895be8292e93a3b7e93ec2f5ade9deed.zip.