watchOS 4.0 (build 15R5365a) is an official Apple over-the-air update for the Apple Watch (42mm), released on 2017-08-22T16:58:29Z. The update package is 527.79 MB. This is a delta (partial) update that requires 3.2.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: c7955cbb80cc75bbf9617386c896d06d0c1bb0cf.zip.