It’s in the very first thread post: climate.py and alarm_control_panel.py. The actual enhancements aren’t relevant to this discussion. However, here’s a thread for Enhanced version of MQTT HVAC which was a result of an earlier thread.
And do you know if they broke some other mqtt stuff?
They didn’t break anything, the Breaking Change did it.
If not i’d suggest to “fix” the official component and have this solved once and for all (and others)
Have you seen the submission process? It’s a steep hill to climb for hobbyists. The ability to tweak a standard module for one’s own purposes (and to easily share it with others), without the submission process, is an enormous advantage.
It used to be very easy to install/share this kind of customized component (copy the modified file into the correct folder and done). Now, “very easy” is not something I could comfortably use to describe the process. Plus the purported advantage of this change failed a real-world test.