The Google app is getting ready for Google Home voice calls in version 7.9, the latest version of the app which is now being updated for users, keeping in mind that not all users will have the update immediately as for right now, this is only hitting beta program users with the update being rolled out to everyone in the weeks ahead.While Google Home voice calls is not currently an active feature that can be accessed through the use of the Google app, it is coming and now Google is laying the foundation for getting everything up and running for a later version.
Google Assistant will naturally be the controller for initiating calls through a Google Home speaker, and it looks like once the feature goes live, only Google Home will be compatible which means any other speakers which come with Google Assistant won't be usable for voice calls. That doesn't mean others speakers won't eventually work. It's also worth noting that this won't work for making emergency calls, so those will still have to be done through a mobile phone.
In addition to prepping the app for Google Home voice calls, the Google app is also preparing for proactive notifications through Google Home. These will only be for certain types of notifications, such as boarding times for flights, meetings, calendar events, upcoming flight information, and traffic delays or issues among other things, and not your run of the mill notifications for every app like Facebook, Messenger and more. These will especially useful for anyone with a busy lifestyle and doesn't always have the time to check alerts for these things on their device, or for anyone that tends to be forgetful and could benefit from having Google Home bringing these to their attention. One final notable change in this most recent version of the Google app is a new string (alongside previous strings from an older version of the app that were there for a little while) for the "Bisto" device type, referencing the ability to finish headphone setup, which suggests that Bisto will be some sort of audio device, though there is still little detail on this. If you're in the beta program, you should already have the update, and if not it should be coming along soon.