Google may add Project Fi integration to Voice in the future following a new rumor that states Google is actively working on a solution in regards to subscribers of the service getting integration with Google Voice. While there is no official confirmation from Google at the moment about the integration happening or what it would include if it does happen, Google has reportedly commented on the matter in some fashion and are said to have recommended that Project Fi users continue to use Hangouts, but that there is a solution being worked out which could very well suggest that they're trying to figure out how to best implement that integration.
While there is no integration at the moment, the notion of it being on the horizon comes after a fairly big update of Google Voice on the web and in the Android app last week where Google overhauled the user interface and gave it a brand new look. Just a few days later it was rumored that Google may be adding VoIP calling to Google Voice down the line, a feature that may play well with Project Fi integration.
What makes the possibility of integrating Project Fi in some way with Google Voice that much more intriguing, is that Google essentially made those switching to Project Fi choose between keeping their Google Voice number to use as their Fi number or porting their wireless carrier number, but if they weren't porting their Google Voice number over to use then they lost it, and haven't been allowed to use Google Voice with the account that's associated with the Project Fi service. Now with integration between the two services potentially in the works it could mean that Google is considering the idea of enabling Google Voice access for those that subscribe to Project Fi as their wireless carrier, or they could be looking to turn the Google Voice app into the main hub for communication for Project Fi users instead of Hangouts being the go-to app for that purpose, which, could make sense given that Hangouts has been driven by Google more in the direction of Enterprise use as of late.