WhatsApp's latest voice calling feature that had been under testing is finally available. The WhatsApp voice calling feature is enabled in the latest version of the WhatsApp Messenger that is now available for download for Android devices on Google Play (version 2.11.561).
However, the feature doesn't come right away to the users. Those who want to have the voice calling feature will need an invite, in the form of a WhatsApp call from any other WhatsApp...