Speculations doing the rounds that Google Duo, Google's video calling app, works on devices that don't have the app installed. However, if the someone without Duo installed wants to make a call, then they'll have to install the app first.
This feature could be deemed as a masterstroke for Google Duo app resulting in increased app usage. A user on Reddit recently spotted that his handset was showing to make a Duo call to a Nexus 6P device, even though the device did not have Duo app installed on it. Users further said that it was possible to make a call to the Nexus 6P handset. It works nearly exactly like a normal Duo call, including the Knock-Knock feature. Users who received a call from a Duo user but do not have Duo installed themselves can answer the call by dragging the phone icon up. Additionally, these users will also get a notification, which will allow them to block a caller from contacting them, or if you choose to continue receiving calls.
An incoming call can instantly fly over the screen with a view of the caller's camera. But, most of the Google messaging apps are caught up in a hitch at this stage, pushing few users towards either Allo or Duo.
This works with audio-only calls as well. So, we're also opening up this feature to developers with an early access program, allowing them to extend the reach of their messaging app. The App Preview version lets you do pretty much everything the Allo app lets you do, including responding to messages and changing the size of text. However, on iOS and platforms, the app will be required for making calls on Duo.
The increasingly tech-savvy user base of the 21st century is quite hung up on messaging apps, and Google messaging apps are high up on the popularity list of such apps.