watchOS 6.3.1 (build 17U224) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2026-02-02T18:44:37Z. The update package is 177.09 MB. This is a delta (partial) update that requires 6.2.8 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: cb24c5e3f511c6f98a606f2c7c00d617bbf47da7.zip.