Apple released the iOS 18 Developer Preview Beta 4 update (build number: 22A5316j) to iPhone and iPad users early this morning.

Notably, in addition to the new CarPlay wallpapers and Control Center features, China Telecom users have discovered the addition of a function switch for WLAN Calling (also known as Wi-Fi Calling) in the settings.

Currently, this function is only available to China Telecom SIM card users after updating, enabling them to make phone calls using WiFi networks, including emergency calls.

This is similar to the VoWiFi technology currently being tested by China Telecom and China Unicom. Last year, China Telecom became the first to support WiFi dial-up voice and video calls in Guangzhou, Shenzhen, Dongguan, and Foshan.

It allows users to make and receive calls directly through connected WiFi signals, meaning that regardless of the phone's SIM card signal, clear calls can be made as long as there's WiFi.

In today's high-rise, bustling cities, there are often areas with no signal, and VoWiFi can effectively solve voice and messaging issues caused by weak coverage in residential areas.

Hopefully, in the future, iOS can deeply integrate with this function to improve the poor signal reception of iPhones.