Microsoft said that future versions of its near-ubiquitous Office productivity software will allow users to save documents not just in its own proprietary formats but also as Open Document Format (ODF), Portable Document Format (PDF) and XML Paper Specification (XPS) files. These are standards operated by third parties that many people use to avoid being tied into Microsoft formats.
The European Commission is investigating Microsoft on two counts, one of which is the claim that it is stifling competition in the software market by failing to make its software and operating systems interoperable with other people's systems.
The Commission said that it would need time to assess to what degree Microsoft's concession affects its case against the firm.
"The European Commission has taken note of Microsoft's announcement on 21st May concerning supporting ODF in Office," said a Commission statement. "The Commission would welcome any step that Microsoft took towards genuine interoperability, more consumer choice and less vendor lock-in."
"In its ongoing antitrust investigation concerning interoperability with Microsoft Office, the Commission will investigate whether the announced support of ODF in Office leads to better interoperability and allows consumers to process and exchange their documents with the software product of their choice," it said.
Microsoft had previously issued a converter which allowed users of its Office software to export documents in ODF, but it has now said that it will fully integrate that ability into versions of Office 2007 from early next year, alongside the ability to export documents as PDFs and XPSs.
The British Educational Communications and Technology Agency (Becta) last week filed a complaint with the European Commission over interoperability, having first complained to the Office of Fair Trading.
The Commission previously investigated Microsoft over its interoperability and last autumn the Court of First Instance backed its €497 million fine of 2004 over the issue. It announced its new investigation in January of this year.