watchOS 5.2.1 (build 16U5113a) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2019-05-07T17:19:39Z. The update package is 201.74 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: a5cc374ac9cbec830c8ea7f1ac375680d3d43f4b.zip.