To take advantage of XSTL 2.0 and XPath 2.0, use Saxon as the XSLT processor. Simply add it as a dependency of the plugin as follows.
<plugin> <groupId>net.sf.xsltmp</groupId> <artifactId>xslt-generator-maven-plugin</artifactId> ... <executions> ... </executions> <dependencies> <dependency> <groupId>net.sf.saxon</groupId> <artifactId>saxon</artifactId> <version>8.7</version> </dependency> </dependencies> </plugin>