Operator Settings Update allows the user's operator to update the operator network and related settings to improve cellular mobile network connectivity and performance. In addition, the operator settings update also adds support for functions such as VoLTE or Wi-Fi calling.

In addition, iPhone SE, 6/6s and other models were unable to experience the Volte function before. You may experience this feature after updating the operator settings.

When the operator settings update is available, the system will prompt the user to install it. If the user's operator issues a mandatory update, the user will see an "OK" button instead of an "Update" button to inform the user that the update has been downloaded and installed.

If users insert a new SIM card into iPhone or iPad, they need to download the operator settings of the new operator.

Four major operators in China:

There are four major operators in China, China Mobile, China Unicom, China Telecom and China Radio and Television. These four operators are the largest and most powerful in terms of communication and ground network. Of course, they have different emphases, such as:

1. China Mobile mainly engages in GSM, TD-SCDMA, TD-LTE networks and fixed networks.

2. China Unicom mainly engages in GSM, WCDMA, FDD-LTE and fixed network.

3. China Telecom mainly deals in CDMA, CDMA2000, FDD-LTE, TD-LTE networks and fixed networks.

4. China Radio and Television is mainly engaged in data transmission services on domestic Internet and domestic communication facilities services.