version and URI for XSLT 2.0

I am in the process of converting my stylesheets over to XSLT 2.0 using 
Saxon to process them.  I noticed that although I neglected to update 
the stylesheet element attributes it still works with the new 2.0 
features.  That is, it still looks like:
<xsl:stylesheet version="1.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>
...
</xsl:stylesheet>

What should version= and xmlns:xsl= be set to?

Thanks,
Barry