watchOS 9.0 (build 15U70) is an official Apple over-the-air update for the Apple Watch (42mm), released on 2018-07-09T17:07:41Z. The update package is 1018.19 MB. This is a delta (partial) update that requires 8.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: b3278ec9a59d0c36f9ec68288ad82ba167466683.zip.