Apps using Apple’s software development kit (SDK) to integrate calling services will be banned in China as part of new regulation from the country’s Ministry of Industry and Information Technology.

News website 9to5 Mac, which reported the news, said China’s government “likely takes issue with the voice over internet protocol functionalities” of CallKit, the functionality in question.

“Such services are frowned upon in the country,” the news outlet added. Apple removed Skype in 2017 for a similar reason.

It is possible the government, which likes to keep a close eye on the internet, is concerned CallKit allows users to avoid censorship and surveillance.

In August 2017, Apple removed some VPN applications in China, following regulations to crack down on services which bypass the country’s massive firewall to access overseas sites. In December, CEO Tim Cook said these apps would be reintroduced, as he stressed the importance of internet freedom.

However, it looks like Apple continues to cooperate with the government’s stance and sent notices to developers using CallKit stating they must remove the functionality and resubmit the app for review.

Their other option is to remove the app’s availability in China.

WeChat, a popular messaging app owned by Chinese internet giant Tencent, may have seen this coming as it removed CallKit some time back, having backed it for a short period of time.

Apple’s website states “CallKit lets you integrate your calling services with other call-related apps on the system. CallKit provides the calling interface, and you handle the back end communication with your VoIP service. For incoming and outgoing calls, CallKit displays the same interfaces as the Phone app, giving your app a more native look and feel.”