mrproject file validation

Greetings-
I'm working on a Senior Project to implement a Java version of a 
MrProject/MSProject style program.  One of our goals of this project is to 
provide compatibility with MrProject files.  

We've ran into a snag when it comes to XML document validation.  Newer 
.mrproject files don't have a DOCTYPE declared within them and the .dtds 
included with the source code are for older versions of MrProject.

I'm wondering what measures are used to validate the integrity of the project 
files.  Perhaps an XML schema is used now?  Any information on this subject 
would be much appreciated.

Thanks-
Thaddeus Quintin

"Vision without action is hallucination"
-Clarence Cuthbertson