| SAXONICA | 
The XHTML output method is not used by default (that is, not unless explicitly requested) if the
            principal stylesheet module specifies version="1.0".
         
If an xsl:key definition is in backwards compatible mode (that is, if the stylesheet specifies
            version="1.0") then the value of the use expression in the key definition and
            the value supplied in the second argument of the key() function are both converted to strings
            before comparison.
         
In <xsl:number level="any"/>, where a from pattern is specified that does
            not match any preceding or ancestor node, Saxon has in the past behaved as if the from pattern selected the root of the tree.
            In fact the specification is that the instruction should return an empty sequence in this case, and Saxon has been changed
            to conform to this. (Note that the XSLT 1.0 specification is unclear what should happen here, and XSLT 1.0 processors
            give varying results.)