The question was asked but deleted by the asker before it received an answer. Because I believe the question is sound and legitimate and serves a purpose, I'm asking it again and provide the answer I already wrote for the original question.
Will XPath 2.0 and/or XSLT 2.0 be implemented in PHP some day or are there any plans?
See this list of XSLT engines, from a thread on an XSL mailing list regarding XSLT 2.0 development.
A solution for PHP is to use the PHP/Java Bridge and Saxon, and follow a tutorial.
The current status of development for XSLT 2.0 (and XPath 2.0) means that there are no plans currently, so there can't be any for PHP either. To use XPath 2.0, you need to include Saxon 9.x and inter-operate with the Java libraries.
Even if someone wrote an open source native library for XPath 2.0 and XSLT 2.0 today, it would take time before it would be suitable for production.
Saxon C was built having this (PHP) use case in mind. This is a Saxon XSLT 2.0 processor and now it can be used from PHP.
More specifically, here is the information from the documentation on how to build the PHP extension: