There's no testing of plugins against previous versions of Heat - APIs that are available to plugins are designed for some degree of backwards but not upwards compatibility. I'd guess that there's a decent chance it would work with Juno, but very little chance for Icehouse due to changes in the way resource plugins talk to clients.

In any event, to try it you just need to copy the Python file defining the plugin to your plugins directory (which is configurable in /etc/heat/heat.conf, but most likely /usr/lib/heat by default) and restart the Heat engine process.