I could previously adjust the heating up/down by half °C using the slider in HomeKit. This no longer works in iOS 13. What is interesting is that you can ask Siri “Set thermostat to 22.5°C”. Siri will report that temperature is now 23°C. When you check in HomeKit it is 22.5 °C, but when you go to adjust the slider it then reverts to 1°C adjustments.
I could previously adjust the heating up/down by half °C using the slider in HomeKit. This no longer works in iOS 13. What is interesting is that you can ask Siri “Set thermostat to 22.5°C”. Siri will report that temperature is now 23°C. When you check in HomeKit it is 22.5 °C, but when you go to adjust the slider it then reverts to 1°C adjustments.