One of my goals in moving to HestiaPi was wider home automation, and MQTT is a widely used standard for that. Sadly, HestiaPi Original (not Touch) doesn't have MQTT on it out of the box, so I developed my own! Open source rocks, right?
I've posted all the details on my blog - you can read my goals & aims in Part 1 of my Home Automation series. If you want to jump straight to "How do I install this?" then check out Part 2. Part 3 details the OpenHAB side. If you just want the code, head to my GitLab project.
Comments, corrections, and contributions are always welcome. The
hestia_mqtt app is still quite rough around the edges, although I'm slowly adding tests to ensure it does what it should