Following months of promises and multiple delays, Facebook-owned WhatsApp, which commands more than 800 million active users worldwide, on Tuesday started rolling a voice calling feature in its iPhone application.
WhatsApp Calling is a staggered release and will be rolling out “slowly over the next several weeks,” the company said, meaning it may not be available for you immediately.
In addition to calling other people for free over Wi-Fi networks, regardless of where they may live, the app has gained other enhancements, too, starting with a much welcomed app extension on iPhones running iOS 8. Sadly enough, this update hasn't brought out support for iOS 8's Interactive Notifications.