XSLT Transformer for Bugzilla

Good Day all,
    I was given the below instructions:

Check your Bugzilla 3.0 bugzilla.dtd and make sure your 2.16.6 xml files
still conform. They may need to be updated. You can use XSLT transforms
to do this. Once you have valid Bugzilla 3.0 xml you  can import them
with importxml.pl.

If any can assist me with the following:

As stated above I need to verify that my 2.16.6 XML file conformto the
bugzilla.dtd in 3.0.  How can I do this? Is there a script that can do this?
Or is XSLT transforms a scipt I can download to do this?

I am in dire need to getting this completed today?  Anyone who can assist
please advise?