Google is doing everything it can to get more people onto its video messaging service. Duo hasn’t set the mobile world alight since it launched in August 2016, especially as there are so many similar apps out there, but a new feature could see its popularity rise: being able to call contacts who don’t have Duo installed.

The ability to make calls to people who haven’t registered for the service arrived in a recent update. It's made possible through Google’s App Preview Messaging feature, which allows Android users to send messages through their messaging app to any of the contacts in their phonebook, even when the receiver doesn’t have the same app installed.

There are a couple of limitations with the system: while it is a cross-platform app, you’ll only be able to use this feature with Android owners who don’t have Duo installed—iPhone users have to download the app to try it. Additionally, the contacts will need to have added a phone number to their Google account.

The system still uses Duo’s ‘knock knock’ feature. When a person receives a call, they see a full-screen live video feed of the caller even before they answer. And once a call is completed, users are asked if they would like to install the app.

Google has a battle on hands trying to drag people away from the likes of Messenger, WhatsApp, and FaceTime, but this new feature and the fact Duo comes preinstalled on some Android phones should help it compete in a crowded market.