Since Home Assistant Core 2022.12, a warning is issued in the logs if a sensor entity that has a device class uses unit of measurement and state class incorrectly, taking their device class into account.
An invalid use would be a sensor entity that has a device class of
SensorDeviceClass.TEMPERATURE but uses
the unit of measurement
% instead of
°F; or the state class
There will be a six-month deprecation period to ensure all custom integration authors have time to adjust. As of Home Assistant Core 2024.8, the warning will then be replaced by an exception.