watchOS 5.2.1 (build 16U5091b) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2019-04-08T17:12:56Z. The update package is 102.99 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: 19dbc1e516ce0ff27950a6389281964d872a6c7a.zip.