watchOS 4.3 (build 15T5212a) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2018-03-16T20:09:14Z. The update package is 325.6 MB. This is a delta (partial) update that requires 4.2.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 01ace70052efee038f58fe05b5c772e5dff0748f.zip.