This week, a select group of testers were granted access to the Office 15 Technical Preview build. As this program is under a non-disclosure agreement, nothing can be shared about how it has progressed from previous leaks and screenshots which were published.
The current “Office 15” codename encompasses the entire Office Family which is; Office, Office 365, Exchange, SharePoint, Lync, Project, and Visio.
While the current builds have only been made available to a select group of testers, you can expect a public beta later this summer.