HA is moving to kelvin as the preferred color temperature unit

[ruttromp]

Home Assistant users using Z2M may see this warning in their logs since HA version 2025.x:

Got color_temp argument in turn_on service, which is deprecated and will break in Home Assistant 2026.1, please use color_temp_kelvin argument

Background information about moving from color temperature to kelvin: https://developers.home-assistant.io/blog/2024/12/14/kelvin-preferred-color-temperature-unit/

Should the Z2M project go along with this development or not?

[Koenkk]

@jbouwh confirmed to me this is not breaking, so Z2M will keep using mireds (as that is also what the ZCL spec uses)

[jbouwh]

Right, The MQTT lights can now process Kelvin values natively to avoid double conversions if Kelvin is to be supported. It is okay to stick to mireds.

[srnoth]

Looks like this did end up being a breaking change in 2025.3.0.

#26623

[Jappe62]

Where ever any lights are sold, color temperature is always presented in Kelvins.

This is the first time I have seen mireds used.
Does not matter what the backend uses, would just be a nice thing to have a switch in the settings to change between the units.

Nobody is forcing me to use Fahrenheit, or a 12-hour click. Please, for a love of all the gods, do not force me to use mireds.
It just confusing and gives me headaches and I, and everybody around me suffers.

Yours,
J

[jbouwh]

MQTT JSON lights still supports mireds, but that will be converted to Kelvin.