Microsoft continues to slowly trickle out bits of information about its Office 12 suite. On Thursday the company will announce that it plans to make XML-based file formats the default in the version of Office due to ship in the latter half of 2006.

Microsoft is introducing the new formats as part of Office 12, officials said, and will share more details about them at next week's Tech Ed 2005 conference in Orlando, Fla.

The new Word, Excel and PowerPoint formats will be designated as .docx, .xlsx and .pptx , respectively. Microsoft is referring to the family of new formats as "Microsoft Office Open XML Formats."

Microsoft is committing to publish the forthcoming XML formats and make them available under the same royalty-free license under which the current Office 2003 file formats are. Licensees will be able to integrate these formats into their servers, applications and business processes "without financial consideration to Microsoft," according to the Redmond software vendor.

For users of older versions of Office — specifically Office 2000, Office 2003 and Office XP — Microsoft will make available software downloads that will allow them to read, edit and save using the new file formats. Microsoft also plans to release a conversion tool that will allow users to point to files in an older format and convert them en masse to the new Office 12 XML format.

And for users who want no part of the new formats, Microsoft also will provide as an option in Office 12 the ability to continue to use the existing Office 2003 file formats as their defaults, officials said.

"We wanted to make sure we didn't repeat the errors we made with Office 97," explained Jean Paoli, senior director of XML architecture for Microsoft. "A big part of our thinking was to make sure everything would be backwards-compatible."

(Microsoft's decision to change the default Office 97 file formats caused chaos for many users and software-vendor partners.)

While industry watchers acknowledged there could be some hidden "gotchas" that will become evident once partners and users get their hands on Office 12 code (Beta 1 is due out this fall), they were upbeat about Microsoft's file-format plans.

Making XML the file-format default "was the right thing for Microsoft to do," said Peter O'Kelly, a senior analyst with The Burton Group. "Invariably, there will be disruption for some people, but Microsoft is providing mechanisms to minimize that disruption."

"This is the direction Microsoft had to go in to take Office the next step forward," concurred Jim Murphy, research director with AMR Research. "It will enable Office to integrate better with other systems, as well as improve the ability to integrate between desktops and enterprise applications."

Next Page: Read More About Microsoft's Office 12 File-Format Plans