watchOS 6.3.1 (build 17U224) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2026-02-02T18:44:25Z. The update package is 697.56 MB. This is a delta (partial) update that requires 6.0.1 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: 2088949f04b8c5e5c70c4115bbbdb9f1ccbe2eed.zip.