Initially, this feature appeared in the October beta of the messenger for Android, but it has only reached the release version now. It may have taken developers longer to gather information about the health of the upcoming innovation.
The app still uses your phone number, but it does not charge for either local or international calls. Voice and video communication is based on an Internet connection, which means that you will not be able to use WhatsApp to call emergency services.
In addition, WhatsApp, unlike Skype or Viber, can be used exclusively for calls within the service. In other words, you will not be able to get through to a fixed or unconnected mobile phone. It is possible that such an opportunity will appear with one of the upcoming updates.
As for the video calling function itself, it is not fundamentally different from all other services. However, now the application interface provides an additional handset key that allows you to make a call to the subscriber. During a conversation, there is a possibility to switch between the front and main cameras, as well as mute.