watchOS 4.3.1 (build 15T5555c) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2018-05-01T17:06:43Z. The update package is 83.21 MB. This is a delta (partial) update that requires 4.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: e1cc39bad2e254c7939171d8fb9af19b42b245f5.zip.