Whatsapp is best and fastest chatting messenger ever made and is continuously improving by adding new features in the app. They are fixing bugs that came after update from time to time.
After the voice call feature introduced by others, sooner or later they will have to announce about voice calls and finally they are doing it. Voice call feature is currently under process in next update of application.
Whatsapp have not yet declared it finally but we are expecting that this feature will be available with next update of whatsapp iPhone app. Though they also have updated permission that indicate its launch in next update but still as it not officially announced so i believe that it is not present.
Whatsapp was purchased by facebook for 19 billion in past. Its free for a complete whole year and after which only 99c are charged for purchase. With tons of features Whatsapp helps you get connected socially with family friends and circle.