Other similar interfaces are also available, but CallKit provides a more natural impression for third-party applications. This triggered the Chinese government's objections regarding the use of VoIP by developers using CallKit.
Last year, Apple had to remove the Skype app from the App Store in China for the same reason. At that time, a number of US legal entities expressed their concerns due to Apple's decision to meet China's demand that they value too quickly.
Apple recently sent a memo to developers who have apps on the App Store that could be affected by Chinese government requests.
The memo noted that the Chinese Ministry of Industry and Technology requested that CallKit be disabled in all applications available in its country's App Store.
Because the application is not permitted by the Chinese government to use CallKit in active conditions, Apple advises developers to make changes and re-register their applications for approval.
Unfortunately, Apple is called to follow the Chinese government to operate in the country.
The relationship between the United States and China is in poor shape right now, thanks to competition in the realm of commerce, and China's actions to Apple are called the effects of this condition.