"OpenXML can be implemented for a range of applications," Elop told in an interview. "Some are characterized as strict and some are more broad in scope. We do our best to expand the standard in collaboration with the standards bodies and implement it ourselves. We have taken major steps, but in some areas more work needs to be done."

Microsoft recently faced criticism because the new Office 2010 productivity suite didn't implement the strict ISO-approved version of OpenXML but a version that had been rejected.

Elop dismissed the criticism, but declined to explain the considerations that Microsoft took. He argued that customers are happy with the current state of affairs and that Microsoft will take additional steps based on customer feedback.