WhatsApp has made end-to-end encryption a default feature, stepping a way forward for the online privacy of its users around the world. The popular messaging app has been criticized over the years for a series of security and privacy issues, but after the announcement of this rollout, it has been praised over the internet by security folks. So far, it only works on Android platform (with iOS coming soon) and covers only text messaging. The app is now open to potential man-in-the-middle (MitM) attacks because there’s no way to check or verify the identity of the person you are messaging.
Source: https://thehackernews.com/2014/11/whatsapp-messenger-app-adds-end-to-end.html