watchOS 5.3 (build 16U5558b) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2019-06-24T17:25:30Z. The update package is 196.55 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: fb18f3a7af8c2a5758d7eb6d168dcb876d1f472e.zip.