XPath 3

XPath 3 is the latest version of the XML Path Language, a query language for selecting nodes in XML documents. It supersedes XPath 1.0 and XPath 2.0.
XPath 3.0 became a W3C Recommendation on 8 April 2014, while XPath 3.1 became a W3C Recommendation on 21 March 2017.

New features in XPath 3.0

Compared to XPath 2.0, XPath 3.0 adds the following new features:
; Inline function expressions
; Dynamic function calls
; Union types
; Namespace literals
; String concatenation operator
; Mapping operator

New features in XPath 3.1

XPath 3.1 mainly adds support for array [data type|array] and map data types. These types and their associated functionality are intended to ease working with JSON data.
Another innovation is the arrow operator => for function chaining. For example, the XPath 2.0 expression
can now be written