watchOS 3.1.3 (build 14S958) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2016-12-21T18:29:56Z. The update package is 130.99 MB. This is a delta (partial) update that requires 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: 0f1fd5ea441e36ba4cd563e2c5731b5320064917.zip.