Ever noticed how the iPhone now treats calls equally, whether they’re from Skype, WhatsApp or an actual telephone? Thanks to a little piece of software known as CallKit, no matter how someone calls you, it looks and behaves exactly the same way -- allowing you to answer and start speaking without having to open the appropriate app.

That feature is going away in China, and users are not happy about it.

Regular call screen on the iPhone (left) and an incoming WhatsApp call with CallKit enabled (right)

Chinese media report that some developers say they’ve been notified by Apple to remove CallKit from all apps available on the App Store in China, citing an order from the Ministry of Industry and Information Technology.

In the the past, China has cracked down on apps that allow users to chat confidentially or get around the country’s firewall. Skype is already banned in China, and WhatsApp, which uses end-to-end encryption, has experienced frequent service interruptions there.

But this appears to be different. If anything, CallKit can actually leave some data out in the open. Information on who you called and how long the call lasted is recorded on the iPhone’s call log -- and, for those who opt in, synced to iCloud.

In China, iCloud data has been hosted by a state-run company since February -- a move that critics say could force the American firm to share information with Chinese authorities. Apple says that data hosted on iCloud in China is protected.

Some users have suggested that CallKit is being targeted not because of censorship -- but rather pressure from powerful wireless providers, which are hoping to drive customers back to paying for regular calls.

Whatever the reason, iPhone users in China are exasperated.

One commented on the Twitter-like microblog Weibo, “So stupid to be removing such a useful function.”

“I keep missing my WeChat calls now,” wrote another.

One user said, “They’re banning everything that’s good for the people.”