watchOS 5.3 (build 16U5545c) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2019-06-11T17:13:46Z. The update package is 157.67 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: db6b327fceab2b5b6f869fb67357c650aae5108a.zip.