watchOS 5.2.1 (build 16U5101c) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2019-04-22T17:13:28Z. The update package is 193.52 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: 19a37bf3eea605f530983e2de5ad026fd5e71da6.zip.