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 °C or °F; or the state class SensorStateClass.TOTAL
instead of SensorStateClass.MEASUREMENT.
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.