When Office 12 debuts next year, the default "save-to" file format of the applications will be XML. Or at least a version which Microsoft is calling Microsoft Open XML Formats.

A company exec was quick to note, however, that the new applications will also support the traditional binary .doc, .xl, and .ppt formats, but unless users designate otherwise, their work will save to the XML choice. The default format can be changed during or after deployment, Microsoft said. With this version of Office, PowerPoint is brought into the XML fold, along with Word and Excel.

Backward compatibility with current file formats is also important. If a Word 2000 user ships a document to someone on the latest Word, changes made by the recipient will automatically save back to the original application's native file format. Thus the new Word will open even a Word 97 file and save information back to that format so it can be read by the originator.

"The roundtrip will be seamless," said Takeshi Numoto, senior director in Microsoft's Information Worker Product Management Group.

If this scenario works as planned, it should please users who have, in the past, been burned by Microsoft format changes even within the same product line. Microsoft will talk more about Open XML and Office 12 at TechEd 2005 next week.

In addition IT or author will be able to designate whether an executable file embedded in that document will be able to run or not, Numoto said.

A document designated with a .docx suffix, for example, will neuter embedded .exe files while one with a .docm suffix will allow them to run.

He also reiterated Microsoft's past pledges to publish its XML format specifications and schemas in advance of the product launch and them as royalty-free downloads.

The current Office 2003 allows users to save Word and Excel documents to its own WordML and SpreadsheetML (XML) formats. The new version adds PowerPoint to the mix. Numoto said those formats, as well as the upcoming iterations, are completely compliant with the XML 1.0 standard.

The file formats were designed to more efficiently encapsulate different data types, Numoto said. The total file is zipped for compression, but individual components are also compressed. So chart information is shrunk down in the way best applicable to that type of data as is the text information. "In some cases we see file sizes cut 75 percent," Numoto said.

Microsoft is doling out tidbits about Office 12 more proactively as the fall 2005 beta approaches. Many say the company still needs to provide compelling reasons for current Office customers to upgrade even off of Office 2000 and XP versions.

One long-time partner was unimpressed with the discussion of XML support. "Unless they're introducing inherent support for SAML or external access to documents to truly facilitate document security, it's not that big a deal," he said. If the "x" and "m" suffixes mean that the code is actually parsed programmatically to avoid code execution, that could be useful, he said. But if users can work around that designation to re-enable the executables, it is "window dressing," he said.