In this open letter to Office developers, Steven Sinofsky, Microsoft Senior Vice President in charge of Office, explains the rationale for Microsoft’s decision to ask Ecma International to assist Microsoft and its partners in pursuing formal standardization of the Office 12 XML format specifications.

Microsoft has also released the text of its covenant not to sue. This text replaces the previous format license:

In connection with our standards submission, we are also announcing a change to our license for the Office XML schemas. While our partners have told us that our current licensing approach is in line with typical standards submissions and the IPR policies at standards bodies, we want to further reduce any remaining questions about our interest in broad use of the document formats for the reasons I’ve already described. We believe a licensing change will help us achieve that objective. I instructed our team to come up with an approach that will settle the issue and clear the way for the broad use of the Office 12 XML formats. What we’re offering is an irrevocable covenant not to sue anyone for use of our XML format specifications. The actual language of the covenant appears here: www.microsoft.com/office/xml/covenant.mspx. The one significant caveat is that we reserve the right to defend our company if an individual or corporation sues us, claiming that our technology infringes their rights.

Update: Brian Jones - New approach to licensing with the Office XML formats