After the announcement of the $19 billion acquisition by Facebook, many might be wondering and asking, "What's up WhatsApp?"

It appears the newest billionaires and millionaires in the WhatsApp headquarters continue working hard to enhance their messaging application. On Friday, alleged images of the soon-to-be-rolled-out voice calling feature of WhatsApp have surfaced on the Internet.

The images of the purported voice over IP interface of WhatsApp appeared on the Apple-centric Italian blog iPhoneItalia. The design of the said UI has a resemblance to the looks of the iOS 7.

The new version of the messaging application will not be too different from the current version of WhatsApp, iPhoneItalia reported [in Italian]. The VoIP feature appears to be on beta and has an easy layout for users. Calls can easily be initiated from an opened chat. The software will seek the permission of the user to use the mobile device's microphone and upon dialing, it displays "WhatsApp Call" to distinguish it from usual phone calls over the network.

Near the bottom of the display will be buttons for "Mute," "Speaker," and "Messages" that can be easily figured out what for. Calls are free and can be made via 3G network or Wi-Fi connection reported iPhoneItalia.

The leaked images also gave a sneak peek of the new button to control the camera of a mobile device that can be used to shoot videos or capture images on the go.

It is not yet clear whether this new version of WhatsApp will be released soon or if the company is still doing some fine tuning before rolling it out to its half a billion users.

During the Mobile World Congress in Spain, WhatsApp chief executive Jan Kourn announced that the company plans to introduce voice calls during the second quarter of 2014 and he believes that WhatsApp's voice offering will be the best in the market since it will not demand too much bandwidth.

While the leaked images have not been confirmed by WhatsApp, no one can deny that the application already features voice messaging, which is just a step behind voice call technology.

When the voice service of WhatsApp rolls out, wireless carriers might need to pop some pills for headache. A research firm forecast that WhatsApp can cause their industry some $33 billion of profits.

Latest reports about WhatsApp also point to possible security weakness of its Android application through which hackers can access user information. The company was quick to deny that the claims were overstatements.