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+--- Thread: KC868-A16 – KCS v2.2.20 MQTT protocol documentation and availability (LWT) (/showthread.php?tid=9915)
KC868-A16 – KCS v2.2.20 MQTT protocol documentation and availability (LWT) - tech1977 - 10-27-2026
Hello KinCony team,
I am using a KC868-A16 (original ESP32 v1.6, not A16v3) with KCS firmware v2.2.20 (build date Apr 2 2026), integrated into Home Assistant via MQTT (Mosquitto broker). Everything works: I control the outputs with {"outputN":{"value":true/false}} on KC868_A16/<serial>/SET and I read inputs and outputs from KC868_A16/<serial>/STATE.
I would like to use all the features of the board, so I have a few questions:
1. Complete MQTT documentation
Could you please send me the latest and complete MQTT protocol document for KCS v2.2.20? I need the full list of topics, commands and payload fields, including outputs, digital inputs, HT1–HT3 inputs, analog inputs (ADC), temperature/humidity sensors, RF 433 MHz, and any other parameter available via MQTT.
2. Availability / Last Will (LWT)
Does KCS v2 publish an availability or Last Will message (online/offline) when the board connects or disconnects from the broker? If yes, which topic and payload does it use? If not, is it possible to add it in a future firmware version?
3. Home Assistant MQTT Auto Discovery
Is Home Assistant MQTT auto discovery supported in KCS v2 for the KC868-A16, or only in KCS v3? If it is supported, where can I enable it?
4. Pulse command with duration
At the moment I use the "delay" output type in the web interface to create a pulse. Is there an MQTT command to send a pulse with a duration specified in the payload (for example "turn on output 5 for 300 ms"), so that the timing can be chosen per command?
5. Other commands
- Is there a command to request the full current state (refresh/query)?
- Is there a toggle command for outputs?
- Can the board publish its state periodically (heartbeat), and is the interval configurable?
- Are STATE messages published with the retain flag, and can this be configured?
6. Values for sensors not connected
I see "temperature":-100 and "humidity":-100 for sensors that are not connected. Can you confirm that -100 always means "no sensor"?
7. Firmware
Is v2.2.20 the latest KCS v2 firmware for the KC868-A16? Is a changelog available?
If you also have HTTP or TCP protocol documents for KCS v2, I would appreciate them too.
RE: KC868-A16 – KCS v2.2.20 MQTT protocol documentation and availability (LWT) - admin - 10-27-2026
1. KCS v2 mqtt document: https://www.kincony.com/forum/showthread.php?tid=3105
2. no this function, KCS v2 will not update now, mainly develop on KCS v3.
3. mqtt auto discovery only work with KCS v3.
4. no this command, you need to set by two different mqtt command for ON/OFF.
5. request all state, see above mqtt document.
6. Can you confirm that -100 always means "no sensor"? --- YES
7. v2.2.21 is newest: https://www.kincony.com/forum/showthread.php?tid=9814 every version changelog showed on the forum thread.
HTTP and TCP protocol all see here: https://www.kincony.com/forum/forumdisplay.php?fid=40