watchOS 4.3.1 (build 15T5565a) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2018-05-07T17:23:08Z. The update package is 150.27 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: db1999ce8d4a94d522c4e4e1922a42d53af3197f.zip.