Z-Wave MQTT Auto Discovery dimmers missing dim level / slider not working (solved)
Posted: Sunday 01 November 2026 17:46
Version: v2026.4 (Build 18581)
Platform: Raspberry Pi 5 (Raspbian Bookworm)
Plugin/Hardware: MQTT Auto Discovery Client Gateway (with Zwave-JS-UI)
Description:
After updating from Beta v2026.4 (Build 18556) to v2026.4 (Build 18581), Z-Wave dimmers integrated via MQTT Auto Discovery (Zwave-JS-UI) no longer update their dim level (level / %) visually in the user interface.
The slider remains stuck completely to the left (0%), and no percentage is shown next to the device, even though the device type is still configured as a "Dimmer" in the switch settings. I have already fully cleared my browser cache and tested in an incognito window, but the issue persists.
Behavior observed:
1. Outgoing control works: Moving the slider in Domoticz successfully sends out the correct MQTT command (Set Level) via the broker. The physical Z-Wave lamp actually dims to the selected value.
2. Incoming status updates fail: When the dimmer reports its status back to MQTT (e.g., {"value": 20, "state": "ON"}), Domoticz Build 18581 processes this update purely as a hard On or Off state. It completely ignores the incoming numerical value / dim level, so the slider and percentage text do not update.
Comparison / Regression proof:
I am running a secondary Pi with the previous Beta v2026.4 (Build 18556) connected to the exact same Zwave-JS-UI instance. On that build (18556), the sliders, statuses, and percentages still work flawlessly. The breakdown of the incoming Auto Discovery payload parsing is strictly isolated to the changes introduced between build 18556 and 18581.
Platform: Raspberry Pi 5 (Raspbian Bookworm)
Plugin/Hardware: MQTT Auto Discovery Client Gateway (with Zwave-JS-UI)
Description:
After updating from Beta v2026.4 (Build 18556) to v2026.4 (Build 18581), Z-Wave dimmers integrated via MQTT Auto Discovery (Zwave-JS-UI) no longer update their dim level (level / %) visually in the user interface.
The slider remains stuck completely to the left (0%), and no percentage is shown next to the device, even though the device type is still configured as a "Dimmer" in the switch settings. I have already fully cleared my browser cache and tested in an incognito window, but the issue persists.
Behavior observed:
1. Outgoing control works: Moving the slider in Domoticz successfully sends out the correct MQTT command (Set Level) via the broker. The physical Z-Wave lamp actually dims to the selected value.
2. Incoming status updates fail: When the dimmer reports its status back to MQTT (e.g., {"value": 20, "state": "ON"}), Domoticz Build 18581 processes this update purely as a hard On or Off state. It completely ignores the incoming numerical value / dim level, so the slider and percentage text do not update.
Comparison / Regression proof:
I am running a secondary Pi with the previous Beta v2026.4 (Build 18556) connected to the exact same Zwave-JS-UI instance. On that build (18556), the sliders, statuses, and percentages still work flawlessly. The breakdown of the incoming Auto Discovery payload parsing is strictly isolated to the changes introduced between build 18556 and 18581.