watchOS 5.3.10 (build 16U711) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm, LTE), released on 2026-03-24T18:37:02Z. The update package is 136.69 MB. This is a delta (partial) update that requires 5.2.1 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: 0f7644bb4e28e4f6fbec5079191ba412b50eaf06.zip.