Microsoft is once again in the race to supply government agencies in the state of Massachusetts with its Office productivity suite, the state's governor has said.

The state was threatening to disqualify Microsoft as a software supplier to state agencies because it failed to support open standards in its Office productivity suite. Starting in 2007, the state requires that all newly created documents use open standards.

Microsoft, however, last week unveiled plans to submit its Office Open XML file format to the ECMA standards body.

If the state follows through on its plan, it could set an important precedent for other governments and give added momentum to Open Office, an open source application backed by Sun Microsystems that uses the Open Document Format.

Microsoft's move has drawn some criticism from open source activists, who consider the proposed opening of the standards 'less open' than ODF. The company, among other things, will retain ownership of the intellectual property covered by the standard.

Sun Microsystems, in response to Microsoft's promise to open its format, sent an open letter to Massachusetts secretary of state Thomas Trimarco that points out that, so far, Microsoft hasn't actually opened the format.

"It [would] be a mistake to rely on a single vendor’s promise to submit a new product to a standards body at some point in the future," wrote Carl Cargill, Sun's director for corporate standards. "The Commonwealth [of Massachusetts] owes no less to its taxpaying citizens."

The standard first has to be approved by ECMA and until then can't be considered open. Sun also claimed that the state should look at the degree of openness – such as developer participation and the level at which multiple developers can participate in creating the standard – before it made any decision.

The letter urged the state to pressure Microsoft into supporting the Open Document Format because it’s the only way to prevent vendor lock-in in the future.

In the past Microsoft has said that it won't support ODF because the standard lacks compatibility with older Office documents and is missing features.