The announcement is a victory for local advocates of people with disabilities, who had fought against the state move to alternatives to Microsoft Office, which they said were less compatible with accessibility tools used by blind, deaf or mobility-impaired computer users in conjunction with Office. It is also a triumph for Microsoft, which views Massachusetts as a key battleground as it tries to maintain Office's dominance.

ODF is a free XML file format used by the free OpenOffice and Sun Microsystems Inc.'s StarOffice, among other suites. It competes with Open XML, the native file format developed by Microsoft for its upcoming Office 2007 suite.

In his official mid-year letter to Governor Mitt Romney, state CIO Louis Gutierrez wrote that early-adopter agencies, including the Massachusetts Office on Disability, will begin using the ODF plug-ins by Jan. 1, 2007. The plug-ins allow Office users to read, create and save files in the aforementioned free XML file format.

"Thereafter, we plan to migrate all Executive Department agencies to compliance with the standard, in phases, by June of 2007," Gutierrez wrote. "In order to meet our implementation timetable, the Commonwealth requires delivery of a translator suitable for use by early adopters by November of this year."

Encouraging the use of non-Microsoft backed file formats could remove one of the greatest incentives for using Office, and loosen the software's hold on more than 400 million users worldwide. A number of European governments, including Belgium and Denmark, have also moved to adopt ODF for official business.