It's based on Z-Wave and runs on Intel and Raspberry Pi. I still use it for lighting at home and I love it.
But the world of home automation is
1. crowded with very large companies, like Amazon and Google
2. there are too many standards and many are closed or obtuse
3. too many devices, with leaders who aren't well known (Aeon, for example)
4. a consumer expectation of free
So, I'm sorry to say, we had to punt.
Yes. That's why MQTT is compelling here.
It's very neutral, similar to why you probably picked Z-Wave. However I do consider something like Zigbee or Z-Wave to be somewhat moot here. Let me explain. A JRiver endpoint or Server that someone would conceivably WANT to automate, is almost certainly connected to a relatively consistent network connection (internally of course). Directly talking to Z-Wave or Zigbee networks makes little sense in that situation. If you're running those, you probably have something to orchestrate all of that like HA or Node Red, taking in data from Z-Wave, Zigbee and MQTT, which is able to actually 'do' something with it.
Maybe if you don't have many other devices Engen makes sense but I don't really believe it's the right approach here.
Home Automation comes up a lot with my clients and for technically inclined ones, they've really enjoyed HA / Node-Red. Most of us use Zigbee / Z-Wave lights, switches and sensors, it's a no-brainer. Those protocols will work with just about anything if you orchestrate things correctly, and not bog down your wifi (I picked up a job last year from a guy who was running 90 Wifi smart devices like lights and sensors and wondered why his network stability was terrible....). However for a computer? Use MQTT over network. That's just the most logical solution.