What's new with the new DirectX 9c (March)?

There's a new version of DirectX 9 out, and I was wondering what's new with it.

Heres the link to it on FileHippo: http://www.filehippo.com/download_directx/

Thread about this here

http://forum.piriform.com/index.php?showtopic=21090

Perhaps you could continue with this subject there