Enable Voice calling on Whatsapp on Android
Whatsapp has been working on the Voice Calling feature for Android. This is similar to other apps like Skype, Viber, Hangouts etc. However, not everyone had this feature enable or get this feature by default.
To get this feature, you have to update your Whatsapp to the latest version (Version 2.11.561) from the Google Play Store. Once you have the latest version, ask any of your friends who have this feature to call you via Whatsapp.
Once you receive the call, Kill the Whatsapp App and then re-open it (Go to Settings –> Apps –> Running programs –> Whatsapp and press Force Stop).
Now start the Whatsapp again and you will have the new voice calling feature enabled in Whatsapp. There will be tabs for calls, chats and contacts.
Call your buddies and help them enable this feature.
This feature is yet to be rolled out on other platforms including iOS and Windows Phone. Also, this works only if you and your buddies have the latest version of Whatsapp.