watchOS 9.0 (build 13V5143a) is an official Apple over-the-air update for the Apple Watch (42mm), released on 2016-03-07T20:57:28Z. The update package is 537.13 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: 671d9afede44f82a5cfcfdd95a9b2880aa06cf17.zip.