The XMLSchema URL is out of date

I received this message from one of our developer's. She is refering to the
-15 schemas. I have not seen anything newer. 

I spent a few minutes browsing around the W3C trying to find the correct URL
and then gave up.
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I am evaluating software that will generate java code based on an xml
schema.  I tried running the SAML Assertion schema through their schema
validator and got the following message:

org.xml.sax.SAXException: The following namespace
"http://www.w3.org/2000/10/XMLSchema" is no longer supported. Please update
to  W3C XML Schema Recommendation.

Perhaps this is something to be sent along to the schema writers?  In case
they are curious, the code I am doing is from the Castor project:
http://castor.exolab.org/ .  
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The meta question is: how does one determine the current correct URL?
Possible answers that do NOT work (at least for me) are:

1. Look for a link on the W3C XMLSchema page

2. Quickly scan Schema-0 and Schema-1, first sections, table of contents and
appendicies.

 
Hal