Microsoft’s next-generation Office, codenamed 15, has reached Milestone 2 according to reports.

The software giant recently compiled build 15.0.2621.1000 of Office 15. Winreview reports that the build marks the Milestone 2 stage of Office 15. Microsoft previously confirmed it was at the planning and preparation stage for Office 15 in October.

Microsoft is planning an improved meeting system and OWA enhancements for the next generation of Office. The company is seeking to employ an Outlook software development engineer at its corporate headquarters in Redmond, Washington. “We are now going to take OWA to the next level and build the next generation clients for desktop and the latest mobile and slate devices,” said a recent the job listing. “The next generation client will include world class messaging, contacts, calendaring and social collaboration for both enterprise and cloud, and will use the latest in web technology.”

ZDNets’ Mary Jo Foley recently attended a day-long “Future of Productivity” event for press and analysts on January 28. Microsoft Business Division President Kurt DelBene spent a brief period speaking about Offfice 15, the next generation of Microsoft Office. “We don’t think we’ve covered all the bases,” said DelBene.”We’re always looking for what new productivity experiences” customers want.” DelBene said that “new applications will join the Office family as a result.”

Foley speculates that a new “meeting” application may be on the short list for Office 15. DelBene said “We have a major investment around making meetings great.” He noted that Microsoft has done work on every phase of meetings — from Outlook invitations, to notetaking (with OneNote), to broadcasting (with some of the new features in PowerPoint 2010). “I could see those pieced together over time,” DelBene told attendees of the Future of Productivity event.

Microsoft is believed to be readying Office 15 for the 2012 time-frame.