XQuery vs X-Query

Wondering which engine people are using, XQuery or X-Query.

What is the official Tamino query engine?
I read X-Query uses XPath, that is known, but the person said XPath lacks features, mainly join.

But if Tamino uses a buffed up version, propriatary, then X-Query might be stronger.

What is everyones opinion.

Use XQuery. XQuery will be a standard W3C recommendation. XPath 2.0 will be a subset of XQuery.

X-Query is a Tamino-specific query language based on XPath 1.0 that was used in earlier versions of Tamino (before standard W3C XQuery had been developed.) It’s only included in the current Tamino versions for backwards compatibility.