We have changed format-number() and some XSLT functions including system-property(), function-available() etc so that the QName-valued argument is now declared with type union(xs:string, xs:QName) rather than xs:string. I believe that there are edge cases where this is an incompatible change -- for example if the supplied value is an xs:anyURI value. I think the edge cases are probably sufficiently obscure and unlikely to occur in practice that it is sufficient to document them.
We have changed format-number() and some XSLT functions including system-property(), function-available() etc so that the QName-valued argument is now declared with type union(xs:string, xs:QName) rather than xs:string. I believe that there are edge cases where this is an incompatible change -- for example if the supplied value is an xs:anyURI value. I think the edge cases are probably sufficiently obscure and unlikely to occur in practice that it is sufficient to document them.