watchOS 6.3.1

watchOS

Version

6.3.1

Build ID

17U224

File Size

154.95 MB

Release Date

2026-02-02T18:44:33Z

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 (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 154.95 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 a3ac96f5cb1aa3a9aa35d35fa1c985d8eea7e599.zip.

Direct URL

https://updates.cdn-apple.com/2025FallFCS/patches/047-01370/357F7169-8C1A-4A1F-8592-DD172724AECC/com_apple_MobileAsset_SoftwareUpdate/a3ac96f5cb1aa3a9aa35d35fa1c985d8eea7e599.zip