watchOS 4.3.1 (build 15T5565a) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2018-05-07T17:23:14Z. The update package is 88.97 MB. This is a delta (partial) update that requires 4.3.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: c0153e0a9b0ec634cf68bdc51d1e45de9deeb14a.zip.