Hi,
I’ve just opened a new PR with initial support for Echonet Lite, specifically to support Mitsubishi Heat pumps (all that I have to test with). It should be reasonably extensible to add support for other Echonet Lite devices. PR is here: Echonetlite Support for Mitsubishi Heat Pumps by mikeb01 · Pull Request #11999 · openhab/openhab-addons · GitHub.
Mike.