watchOS 9.0 (build 13V5129c) is an official Apple over-the-air update for the Apple Watch (42mm), released on 2016-02-22T17:55:56Z. The update package is 542.15 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: 0aba130d4b1d80267d9435b1f310945b142bd0a1.zip.