watchOS 5.2.1 (build 16U5091b) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2019-04-08T17:12:54Z. The update package is 124.86 MB. This is a delta (partial) update that requires 5.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 6d824a11575076dbcd84c89bd2e69d608ab7db03.zip.