Functions, operators, and data types for XPath 3.0

Namespaces defined in the XSLT, XPath, and XQuery specifications now generally begin However, for the xpath-datatypes namespace, the following namespace URIs are recognized:

Saxon treats older versions of the namespace as synonyms for the current (2005/04) namespace when matching type names appearing as an AtomicType in the SequenceType production and in the names of constructor functions. If types in the xdt namespace are used during schema validation of source or result documents, however, the current (2005/04) namespace must be used. Constructs that use these type names to refer to type annotations on nodes, for example attribute(*, xdt:anyAtomicType) must also use the current namespace.

The namespace for error codes is hardly used, but it is nominally Unlike the others, this namespace has not been changed in successive working drafts.