Somewhat fitting that in our 10th season we'll be upgrading to version 10 of the DMB software. You can purchase it via the Diamond Mind website (http://www.diamond-mind.com/servlet/StoreFront) for $29.95.
Databases are not compatible with version 9, so you will need version 10 in order to play h2h or to submit your own MP. Of course, you are not required to have the software, but it does help and it also creates less work for me.