Microsoft officials have been tight-lipped about what the company plans to deliver in the next version of Office client for Windows, codenamed "Office 16."

But a bit of information has begun to trickle out about what looks to be a private "technical preview" of the coming Office suite. This technical preview, which some inside Microsoft also are said to be dogfooding internally, is not the touch-first, Metro-Style version of Office for Windows that some of us Microsoft watchers have been calling "Gemini. " Instead, this is the preview of the next version of Office for "desktop" Windows PCs and devices.

Tom Warren at The Verge posted on September 18 screen shots that are believed to be from the Office 16 technical preview.

Based on those shots, it looks like Microsoft is adding its "Tell Me" tool that's already part of Office Online and Office for iPad to the coming version of Windows. "Tell Me" allows users to ask how to accomplish a task in Office without having to wade through documentation or hunting around within the Office Ribbon.

There's also an automatic image-rotation feature to help users correctly position images in Office documents, the screen shots indicate, as well as a new "black" theme option for Office users (in addition to the current light gray, dark gray and white themes).

But there are more changes coming beyond those indicated in the leaked screen shots, which could be of interest to business users in particular, sources say.

The Excel Data Model is going to be silently updated to a version that will be supported fully only in the new Excel versions moving forward. (The Excel Data Model also is known by some as the "Power Pivot model.) Refresh, edit and query of files using this model, won't be supported without the new Excel version, though users with older versions will still be able to open files.

Microsoft also is enabling panning and zooming on large charts and smart art diagrams in the coming Office 16 release. In Project, Microsoft is enabling users to have multiple Timeline bars and custom date ranges in a single view. And in the new version of Visio, Microsoft is adding information rights management protection for Visio files, which could be welcomed by those using Visio for research and patent information, among other applications.

Microsoft is making some tweaks to how Outlook 16 will look and work on smaller footprint devices. Users will be able to sync mail more granularly. Instead of only being able to download a month's worth of mail, users will be able to download one day, three days, seven days or 14 days worth of mail with the new Outlook.

Microsoft is also adding the ability to attach and share most-recently used local and cloud files on OneDrive (both the consumer and business versions). The idea behind this one is users will be able to share files and collaborate on commonly used files and documents more quickly. Users will have the option to share these files as an edit or view-ony link instead of as a plain-old attachment.

It's not too surprising that these changes are incremental. There may still be some bigger changes coming with the Office 16 client release, but Microsoft increasingly is focusing on delivering new features first (and sometimes only) in the cloud — which means, in Office's case, Office 365.

I've heard rumors that Microsoft may make a public preview of Office 16 — both client and the Exchange, SharePoint and Lync servers — later this fall, possibly October 2014. Sources have said Microsoft's plan is to deliver the final version of Office 16 (which may or may not be called Office 2015 when it's released) in the spring of 2015. That's the same timeframe when Microsoft is rumored to be rolling out the touch-first "Gemini" Office apps.

A spokesperson said Microsoft had nothing more to share regarding the next version of Office at this time. Microsoft officials also are still not commenting on when the company plans to release a new version of Office for Mac .