The fourth beta of iOS 9.2 was released on Wednesday to both registered developers and public beta testers, supporting third-party action extensions within Safari, as well as AT&T's new NumberSync feature.
The fourth beta of iOS 9.2 is identified as build 13C5075. It is available over the air to registered devices through Software Update, via iTunes, or can be downloaded from Apple's developer portal.
The new build arrives eight days after Apple issued the third beta of iOS 9.2 to developers.
The most notable change in iOS 9.2 revealed by Apple is a change to how the Safari Web browser works in third-party apps, enabling user-installed extensions to operate in those conditions. It also supports AT&T's forthcoming NumberSync technology for receiving phone calls across devices.
Users running iOS 9.2 beta to can open the Settings app, choose Phone, then Wi-Fi Calling. From there, tap on Add Wi-Fi Calling For Other Devices, agree to the terms and conditions, and Wi-Fi Calling will be enabled for other devices tied to your iCloud account.