Light entities are now required to set the
color_mode properties, and a warning will be logged asking users to report an issue if that's not done.
In addition, a warning will be logged if the light reports an invalid combination of
supported_color_modes or a
color_mode other than
ColorMode.UNKNOWN, which is not included in the light's
In the Home Assistant 2025.3 release, the warnings will be removed, and lights that have still not been upgraded to a color mode or that violate the color mode rules will no longer work.
More details can be found in the documentation.