watchOS 6.0 (build 17R575) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2019-09-11T18:36:17Z. The update package is 691.35 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: 1a1ce0b11f6ad0f8bdede807afa7e2beb1948d3d.zip.