watchOS 6.3.1

watchOS

Version

6.3.1

Build ID

17U224

File Size

155 MB

Release Date

2026-02-02T18:44:36Z

Update Type

Normal release

Delta update - requires 6.3 installed first.

Download OTA

Looking for beta firmware? View beta builds for Apple Watch Series 4 (44mm) →

About This Update

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 155 MB. This is a delta (partial) update that requires 6.3 to already be installed on the device - it cannot be applied from scratch. This update is currently signed by Apple, so it can be applied directly from Settings › General › Software Update.

The OTA payload file is aafdfa313f88648c5c0e1e47432e804e998f6366.zip.

Direct URL

https://updates.cdn-apple.com/2025FallFCS/patches/047-01381/66C0AA6E-3215-495A-8833-C06C26C90829/com_apple_MobileAsset_SoftwareUpdate/aafdfa313f88648c5c0e1e47432e804e998f6366.zip