watchOS 5.2.1 (build 16U5091b) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2019-04-08T17:12:29Z. The update package is 444.03 MB. This is a delta (partial) update that requires 5.1.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 02cb4452c18a803b24b465c4d7873dddb341d1b6.zip.