No license needed to use the Office Open XML formats

I still get folks asking me questions about the licensing of the Open XML formats from time to time, and it seems there is a lot of misinformation out there. It's actually been well over 7 months since we made the move away from licensing the formats and instead just provided a general commitment to not enforce any IP behind the formats. The legal term for this new commitment is CNS (covenant not to sue). This allows anyone to develop against our formats without having to worry about patents, and this it's irrevocable (meaning it can't be changed in the future).

The CNS is available up here ( Recently we took an additional step to help people who don't want to deal with parsing legal documents, and actually asked an outside law firm (Baker & McKenzie) to do a study for us on both the standardization as well as the CNS. I think any of you folks who've been frightened by some of the FUD that has been spread about the Ecma Office Open XML formats should take a look: (Link)

Some good takeaways I wanted to call out were:

  • "In this case, the CNS is a unilateral statement to the world about Microsoft's future behaviour towards the enforcement of its patent rights contained in the Schema. While the covenant governs Microsoft's future behavior, it is retrospective in effect, applying to any past uses of the Schema that may have been in actual or potential breach of the terms of the preceding Patent License."


  • "By stating that the covenant is 'irrevocable', Microsoft has protected users against a change in company policy at any point in the future."


  • "The CNS is therefore considerably more favourable to a person relying on it, than any form of patent licence because it does not impose positive restrictions on beneficiaries' activities as a condition of relying on it."


  • "Microsoft's CNS is similar to a covenant issues by Sun Microsystems Inc., in September 2005, in respect of any patents that it hold in respect of the Open Document Format ('ODF') for Office Applications (OpenDocument) v1.0 Specification ('Sun's Covenant')."


  • "The CNS does not affect users' rights to create their own applications using the Schema specifications. For example, there are no restrictions in the CNS that would prohibit third parties from incorporating the standard into applications they create and distribute in source code form, or for other hardware or operating-system platforms. Such applications, developed by third parties, will generally be subject to separate legal agreements, licences and covenants that the developers of those applications may impose, such as Sun's Covenant in respect of ODF. "


  • "Any such restrictions will be determined by the development and licensing practices of the third-party developer, not by Microsoft; and this will be as true for applications developed under the ODF standard as it is for applications incorporating the Open XML Schema standard."

Have a great weekend everyone!