Announced a few days ago on the IEBlog:
Why aren’t we supporting XHTML when it’s served as the “application/xml+xhtml” media type in IE7? I made the decision to not try to support the MIME type in IE7 simply because I personally want XHTML to be successful in the long run.
Obviously this is going to disappoint many web developers who’s expectations had been raised by a recent series of encouraging announcements from the IE development team.
Personally, I would prefer Microsoft to concentrate on fixing HTML/CSS bugs and implementing the missing CSS2.1 features. If implementing full XHTML support impacts on the release date of IE7 then my opinion is that we should wait for IE8. But that’s just me. Other web developers may have different ideas.