first showed off Duo at its I/O conference in May, promising that the new app would be very simple focus more on the human element by offering you a live view of the video before answering the call, thanks to the Knock Knock feature. In the launch announcement, says that all calls with Duo are end-to-end encrypted. Beyond that, the app is very simple by design, without any additional connections to messaging or other services. For a deeper dive, you can check out the obligatory YouTube video with lots of happy people. Duo is available now in the App Store ay Store. y this matters: Hangouts has long been a mess, offering a buggy inconsistent experience for video calling messaging. Duo is the first of ’s new, well, duo of apps designed to remedy this. lo is an iMessage-style app that should also launch soon, promising to bring you cross-platform messaging bliss with the smarts of the new Assistant.