Follow these simple steps to activate WHATSAPP CALLING FEATURE.
You will require the latest version of Whatsapp 2.11.561. to download CLICK HERE
Install the downloaded application.
Here, you will need to receive a WHATSAPP CALL from someone who has already activated WHATSAPP CALLING on his phone.
Those who have my number can drop a msg on whatsapp for receiving a call from me. Others can leave their phone numbers in the comment section (on your own risk) to receive a call from me.
Simply wait till they officially release the updated app.