Microsoft reached a development milestone this morning, the beginning of the "Office 15" Technical Preview Program. Office 15 is the codename for the upcoming next-generation version of the Microsoft Office products and services, and the Technical Preview is the first time that Microsoft share their work with a select group of customers under non-disclosure agreements (NDAs).

Because Microsoft are only at the early stages of Office 15, they can't share too much about what's included, or being worked on in the new Office suite of software. Of course, there is a tease. CVP of Development, Microsoft Office Division, PJ Hough, said in the Office Blogs:

At this early point in our development cycle, I'm not able to share too much about Office 15, but I can tell you Office 15 is the most ambitious undertaking yet for the Office Division. With Office 15, for the first time ever, we will simultaneously update our cloud services, servers, and mobile and PC clients for Office, Office 365, Exchange, SharePoint, Lync, Project, and Visio. Quite simply, Office 15 will help people work, collaborate, and communicate smarter and faster than ever before. 

The Technical Preview is already full of users, but Microsoft have promised a public beta of Office 15 for later this summer, and have said they'll share more details on it then.