watchOS 5.2.1 (build 16U6113) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2019-05-13T17:16:24Z. The update package is 82.02 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: 5e2bbe7f26c1b93a341af9e520f35291a973441e.zip.