Unfortunately Home Assistant never specifies the associated config if there is an error. Just check “your” config. The “details” are not saying anything either…very annoying!
Now I get this error:
I can’t find any config where that option is in. My mqtt.yaml is almost empty and does not have anything with rgb in it. Neither my config.yaml.
How do I find the file this error is related to???
Copy-paste the following template into the Template Editor.
{%- for x in integration_entities('mqtt') if 'rgb' in states[x].attributes %}
{{ x }}
{% endfor -%}
It finds all entities belonging to the MQTT integration, searches each entity’s attributes for an attribute named rgb and, if it finds it, reports the entity’s entity_id.
Assuming it finds an entity, you’ll know its entity_id and whether it’s one you configured manually or possibly it was discovered automatically via MQTT Discovery.
Assuming it reports an entity_id, if the entity belongs to a device you can find the device’s name using the following template (replace light.foo with your entity_id).
{% set did = device_id('light.foo') %}
{{ device_attr(did, 'name') if did is not none else 'Not Found' }}
The template is based on the assumption that the “rgb option” exists as one of the entity’s attributes. If the assumption is incorrect then the template will, obviously, report nothing.
Any progress to report after trying my suggestion?
Sorry for my late respond due to circumstances. I appreciate your help.
This template gave me some output but only items that don’t have own config like volvo2mqtt integration. It might be that the option is embedded in this integration. So it needs to be fixed in an update I suppose.
The template reported entities that are created automatically via MQTT Discovery (and they belong to Volvo2MQTT).
In other words, it identified the entities having an rgb attribute that was reported by the error message. It answers your original question of how to find the source of the error.
Please consider marking my post above with the Solution tag. It will automatically place a check-mark next to the topic’s title which indicates to others that the topic has been solved. This helps other users find answers to similar questions.
If you want more details about the exact names of the attributes, you can use this enhanced version:
{%- for x in integration_entities('mqtt') if 'rgb' in states[x].attributes %}
-> {{ x }}
{%- for z in states[x].attributes if 'rgb' in z %}
{{ z }}
{%- endfor %}
{% endfor -%}
Many thanks for your help!
Hey, I am also getting the same error message but when nothing is returned when I populated the template you provided in the editor. Any other way to find the source of this issue?
Use a capable text editor, like VS Code, to search for rgb in all files in the config directory and all its subdirectories including the hidden .storage directory.
I finally solved it.
It turned out the error came from an ESPresense device. I flashed the ESPresense to latest version, removed the device from MQTT integration and it instant popped up again as it was found by the integration. This time without the RGB option and error is gone. 
Hey guys, sorry to revive this after so long, I’m having 7 similar errors (i think they started appearing recently)
2025-08-17 04:01:18.634 ERROR (MainThread) [homeassistant.components.mqtt] The 'rgb' option has been removed, please remove it from your configuration
2025-08-17 04:01:18.634 WARNING (MainThread) [homeassistant.components.light] None (<class 'homeassistant.components.mqtt.light.schema_json.MqttLightJson'>) does not set supported color modes, this will stop working in Home Assistant Core 2025.3, please create a bug report at https://github.com/home-assistant/core/issues?q=is%3Aopen+is%3Aissue+label%3A%22integration%3A+mqtt%22
2025-08-17 04:01:18.638 ERROR (MainThread) [homeassistant.components.mqtt] The 'rgb' option has been removed, please remove it from your configuration
2025-08-17 04:01:18.639 WARNING (MainThread) [homeassistant.components.light] None (<class 'homeassistant.components.mqtt.light.schema_json.MqttLightJson'>) does not set supported color modes, this will stop working in Home Assistant Core 2025.3, please create a bug report at https://github.com/home-assistant/core/issues?q=is%3Aopen+is%3Aissue+label%3A%22integration%3A+mqtt%22
2025-08-17 04:01:18.643 ERROR (MainThread) [homeassistant.components.mqtt] The 'rgb' option has been removed, please remove it from your configuration
2025-08-17 04:01:18.644 WARNING (MainThread) [homeassistant.components.light] None (<class 'homeassistant.components.mqtt.light.schema_json.MqttLightJson'>) does not set supported color modes, this will stop working in Home Assistant Core 2025.3, please create a bug report at https://github.com/home-assistant/core/issues?q=is%3Aopen+is%3Aissue+label%3A%22integration%3A+mqtt%22
2025-08-17 04:01:18.648 ERROR (MainThread) [homeassistant.components.mqtt] The 'rgb' option has been removed, please remove it from your configuration
2025-08-17 04:01:18.648 WARNING (MainThread) [homeassistant.components.light] None (<class 'homeassistant.components.mqtt.light.schema_json.MqttLightJson'>) does not set supported color modes, this will stop working in Home Assistant Core 2025.3, please create a bug report at https://github.com/home-assistant/core/issues?q=is%3Aopen+is%3Aissue+label%3A%22integration%3A+mqtt%22
2025-08-17 04:01:18.652 ERROR (MainThread) [homeassistant.components.mqtt] The 'rgb' option has been removed, please remove it from your configuration
2025-08-17 04:01:18.653 WARNING (MainThread) [homeassistant.components.light] None (<class 'homeassistant.components.mqtt.light.schema_json.MqttLightJson'>) does not set supported color modes, this will stop working in Home Assistant Core 2025.3, please create a bug report at https://github.com/home-assistant/core/issues?q=is%3Aopen+is%3Aissue+label%3A%22integration%3A+mqtt%22
2025-08-17 04:01:18.656 ERROR (MainThread) [homeassistant.components.mqtt] The 'rgb' option has been removed, please remove it from your configuration
2025-08-17 04:01:18.657 WARNING (MainThread) [homeassistant.components.light] None (<class 'homeassistant.components.mqtt.light.schema_json.MqttLightJson'>) does not set supported color modes, this will stop working in Home Assistant Core 2025.3, please create a bug report at https://github.com/home-assistant/core/issues?q=is%3Aopen+is%3Aissue+label%3A%22integration%3A+mqtt%22
2025-08-17 04:01:18.660 ERROR (MainThread) [homeassistant.components.mqtt] The 'rgb' option has been removed, please remove it from your configuration
2025-08-17 04:01:18.660 WARNING (MainThread) [homeassistant.components.light] None (<class 'homeassistant.components.mqtt.light.schema_json.MqttLightJson'>) does not set supported color modes, this will stop working in Home Assistant Core 2025.3, please create a bug report at https://github.com/home-assistant/core/issues?q=is%3Aopen+is%3Aissue+label%3A%22integration%3A+mqtt%22
The above template returns nothing unfortunately.
VScode does not find any results in the .storage directory
Any ideas as to how to find the cuprits?
How long has it been since you updated? You have a warning there which warns about color modes which will be removed in 2025.3 (last March). Given that these warnings usually come with a 6-month warning, your HA version must be between 2024.10 & 2024.2.
Re your rgb warning, if you’re running Z2MQTT, the warning might be caused by that. Check if there are any recent updates you can apply to Z2M.
That’s the odd part, I’m pretty fast with the updates. Usually I update every 1-2 versions (decimals) and I can only remember once that I left 2 full versions without updating.
I’m using z2m, I’ll check if they have updates, although it would have popped up.
Also, the mqtt filter above did not give any results, which is strange
