watchOS 6.3.1

watchOS

Version

6.3.1

Build ID

17U224

File Size

297.81 MB

Release Date

2026-02-02T18:44:33Z

Update Type

Normal release

Delta update - requires 6.2.1 installed first.

Download OTA

Looking for beta firmware? View beta builds for Apple Watch Series 4 (40mm) →

About This Update

watchOS 6.3.1 (build 17U224) is an official Apple over-the-air update for the Apple Watch Series 4 (40mm), released on 2026-02-02T18:44:33Z. The update package is 297.81 MB. This is a delta (partial) update that requires 6.2.1 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 021a40c0012947e781afb2d461b5111a16dd3b7b.zip.

Direct URL

https://updates.cdn-apple.com/2025FallFCS/patches/047-32218/C26734F6-A8DA-4D98-B7C9-E44C30628751/com_apple_MobileAsset_SoftwareUpdate/021a40c0012947e781afb2d461b5111a16dd3b7b.zip