watchOS 5.3 (build 16U5545c) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2019-06-11T17:13:48Z. The update package is 1.28 GB. This is a full OTA update that can be applied from any compatible base version. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 23ee2475c4412f9efad273792e74808df4bf9e71.zip.