Earlier, a few WhatsApp screenshots showcasing this voice-calling feature were leaked online by Androidworld.nl. WhatsApp also released WhatsApp for Web users which simply mirrors whats’s on your smartphone to the screen. WhatsApp for web is currently available through the Google Chrome browser and also supports Android, BlackBerry and Windows Phone. However iOS users can’t access WhatsApp for web. WhatsApp’s voice-calling roll-out comes soon after rival Indian app Hike rolled out for free voice-calling on 2G and 3G for their app. Of course in terms of user engagement, WhatsApp is ahead of it rivals. Facebook, which bought WhatsApp last year, recently revealed that the app has 700 million monthly active users and that over 30 billion messages are shared on WhatsApp everyday. With voice-calling feature coming soon, it’s likely that WhatsApp’s engagement number will rise further.