XRX and XPath 2.0

Here is the truth about XPath in the XRX architecture if you follow the specs literally:

Within the XForms spec, there is a small but important sentence though:

A future version of XForms is expected to use XPath 2.0, which includes support for XML Schema datatypes.

And that is just enough to allow XPath 2.0 usage within Orbeon Forms. It has been supporting XPath 2.0 for quite a long time already by the way.