watchOS 6.3.1 (build 17U224) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2026-02-02T18:44:36Z. The update package is 250.54 MB. This is a delta (partial) update that requires 6.2.6 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: a2f3c40cb9f739e1b25f226d850a9539bfcac4fd.zip.