watchOS 5.3 (build 16U5558b) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2019-06-24T17:25:11Z. The update package is 167.21 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: 6b3a7f5a29a52d34740b99c566ff48f8b17e5afd.zip.