watchOS 6.3.1 (build 17U224) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2026-02-02T18:44:18Z. The update package is 181.23 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: 447b95329ea5e60177a62e70f963b8441df82364.zip.