?
http://blogs.msdn.com/brian_jones/archive/2006/08/04/688932.aspx

>It's not totally open. You need to license the schema. Microsoft has submitted the file format to at least two standards organizations.
>
>>At the recent Office 2007/Vista MSDN event I attended, the speaker stated that the new format is a combination of XML architecture and ZIP compression for size reduction. Microsoft promises the format will be open (published for anyone to use). Older versions of Office can use components provided by Microsoft for Office 2000, XP, and 2003 that will be available to perform document conversion. Now, I didn't see the components myself, so we can only wait and see if such a tool becomes available. I'm guessing that they will be separate from the toolkit for Office 2007 since that is already released for free.
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>>Having written that, XML is a standard format and kudos to MSFT to switching Office to it. Foxpro will not open a VFP table. VFP can read Foxpro tables. I do not expect MSFT to automatically program for older versions to read the structure of newer versions. Office 2007 reads the older versions fine. I see absolutely no fault with MSFT on this. Besides, other than the new features and UI (which I think are really cool), how will MSFT get users to upgrade? How do you get your users to upgrade? They have incorporated a standard format, allowed for size reduction, and added cool ui.
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>>I seldom give kudos to MSFT, but in this case, MSFT deserves it.