Google officially launched its new video calling app Duo Tuesday, which aims to compete with video chatting functionality offered by rivals like Facebook and Apple. As part of the transition to Duo, Google is also starting to deemphasize its existing Google Hangouts video chat, and discontinuing Hangouts On Air live streaming.

Duo, which is available for both Android and iOS, offers one-to-one video calling without many of the bells and whistles known from other apps: There are no stickers or birthday hats, there’s no group video chat and no way to send text messages to other participants.

Instead, Duo focuses on full-screen video calling with a very simple interface, and with an interesting feature dubbed Knock Knock that’s supposed to making video calls less intimidating: Users who are getting a video call can already see the participant who is calling on video before picking up, which is a bit like looking through a peephole before opening the door.

“Knock Knock makes video calling more spontaneous and welcoming, helping you connect with the person before you even pick up,” wrote Google principal software engineer Justin Uberti in a blog post Tuesday.

Google first announced Duo at its Google I/O developer conference in June, when it also previewed a new text messaging app called Allo. Both apps are just the latest in a long string of Google services to tackle messaging and personal communication. Back in 2013, Google introduced Hangouts as a one-stop app for video chatting and text messaging.

However, Hangouts was eclipsed by Facebook’s Messenger and other purpose-built messaging apps. Google told reporters this week that it will continue to support Hangouts, but shift the focus for the service to the enterprise.

As part of that shift, Google is also shutting down Hangouts On Air, a live streaming feature built on top of the messaging service. Google said this week that it will discontinue Hangouts On Air in September, and transition all of its live streaming efforts to YouTube Live.