watchOS 5.2.1 (build 16U6113) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2019-05-13T17:17:00Z. The update package is 145.48 MB. This is a delta (partial) update that requires 5.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 7338c2ce3f1fd7b919f4cbacfeaece1dbbf28a39.zip.