watchOS 6.3.1

watchOS

Version

6.3.1

Build ID

17U224

File Size

542.08 MB

Release Date

2026-02-02T18:44:38Z

Update Type

Normal release

Delta update - requires 6.1.3 installed first.

Download OTA

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

About This Update

watchOS 6.3.1 (build 17U224) is an official Apple over-the-air update for the Apple Watch Series 4 (40mm, LTE), released on 2026-02-02T18:44:38Z. The update package is 542.08 MB. This is a delta (partial) update that requires 6.1.3 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 ff4b9e03f3392209a6f773f1f8947913dce95257.zip.

Direct URL

https://updates.cdn-apple.com/2025FallFCS/patches/047-32179/7B306BEB-D4C2-4BAE-9360-5B6298E3043E/com_apple_MobileAsset_SoftwareUpdate/ff4b9e03f3392209a6f773f1f8947913dce95257.zip