Since its purchase by Facebook some time ago, WhatsApp has only gone from strength-to-strength, adding encrypted messages, voice calling, tweaks to the overall messaging system and now, video calling. This is a feature that has been rumored for some time, and now it appears as though WhatsApp has flipped the switch, making the feature live for the majority of WhatsApp users out there. This is significant, because WhatsApp is arguably the most-used messaging application on the planet, even more so than iMessage on iOS. For a lot of people, WhatsApp is the de facto method for keeping in touch with people no matter what platform they're on, and now with video calling, the app can only become more popular.
At the time of writing, users are reporting that the beta version of WhatsApp, that's version 2.16.318 (451462), and it appears to be working just fine. Some have also reported that the feature has gone live on other versions of the app, but it's likely that an official update to the stable version of the app is coming shortly, as soon as WhatsApp verify there are no issues server-side. The way that this works inside of the WhatsApp app is when you click the call button, the option of either a voice call or video call is provided to users. Video calls appear to be one-on-one right now, but there's talk of WhatsApp introducing group video calls soon, along with a public chat option that has seemingly been in the works for some time now.
For those that have been using the WhatsApp beta for some time now, they can go ahead and update the app to the above version and then get started with video calling. If you haven't joined the beta program, you can do so via the button below. This should give you the latest version, but there are also options to sideload the app from around the web, too. As this is a feature that has just gone live, there might be some teething problems, such as laggy performance and not being able to video call everyone in your contacts list, but as the feature becomes more and more popular, it's likely these issues will be ironed out.