watchOS 4.3 (build 15T5165e) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2018-01-25T18:04:10Z. The update package is 315.11 MB. This is a delta (partial) update that requires 4.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 6b2b2d79d54bd0aeac33450ad05c341bc689a4b3.zip.