primitive datatypes in XML schema 1.0 versus 1.1

Dear XML schema working group,

I am a member of the W3C Rule Interchange Format (RIF) working group.
As the name of the working group indicates, we are developing an
interchange format for rules over the Web.
For datatype support we chose to rely on XML schema primitive datatypes.
The question now is whether we should use XML schema 1.0 or 1.1.

I have seen that the string datatype in 1.1 is a strict superset of the
string datatype in 1.0: every string in 1.0 is a string in 1.1, but
there are strings in 1.1 which are not strings in 1.0.
Is there some exhaustive list with the differences of the primitive
datatypes in the versions 1.0 and 1.1 of XML schema?
Is there any reason you see why we should choose one version of XML
schema over the other?

Thank you in advance for your advice and clarification.

Best regards,
Jos de Bruijn
-- 
Jos de Bruijn            debruijn@inf.unibz.it
                      http://www.debruijn.net/
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As far as the laws of mathematics refer to
reality, they are not certain; and as far as
they are certain, they do not refer to
reality.
  -- Albert Einstein