The decoder files definition files at http://jmri.org/xml/decoders/ are regularly updated from the latest (unreleased) development build.
Due to possible dependencies on more recent JMRI Java code or <xi:include ...> fragment files, these definitions may not work correctly with your installed version of JMRI.
An (unreleased) JMRI development build with the latest definitions included can be downloaded from https://builds.jmri.org/jenkins/job/Development/job/Packages/.