I have a Shelly 2Xi wall display to replace my thermostat. I bound a Blu HT sensor since there is no integrated sensor. The heating works in principle, but the Hysteresis is useless and not recognized. It simply does not work. I set the hysteresis to 0.5°C and the desired temperature to 23.5°C and the heating starts as soon as the temperature reaches 23.4° (and stops at 23.5°). I also tried other values for hysteresis, none worked.
Quite disappointing after I sent back a Wall Display 2X because of Wifi issues.
It's just a minor software bug which should be easy to fix and I can wait because the HT is quite slow so there is some delay integrated, still annoying.