watchOS 9.0 (build 13V5141a) is an official Apple over-the-air update for the Apple Watch (42mm), released on 2016-03-01T18:30:59Z. The update package is 537.14 MB. This is a delta (partial) update that requires 8.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 062e5852c6c7dfc7adfeee5cb93255e69bfd80f8.zip.