watchOS 6.0 (build 17R5571a) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm, LTE), released on 2019-08-21T17:12:21Z. The update package is 710.02 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: fd6c3e276a5a5cc6b5dea3d82d03da31edbeec25.zip.