Since two versions ago, we have a new “update” sensor. This sensor can’t be created using MQTT discovery. It will be great to be able to do so, for example, to detect/upgrade firmware in Zigbee2Mqtt.
It was a PR waiting for this to be implemented in z2m: https://github.com/Koenkk/zigbee2mqtt/pull/11999
Until now, a standard sensor with the “update” state exists, but is less powerful than the new update sensor.