<![CDATA[[MQTT-Core] Support for RETAIN]]>RETAIN is an essential feature of any MQTT implementation. Without RETAIN, device information can get lost when a service like Home Assistant who uses MQTT subscription to get device info, has an issue. For instance, when Core sends out an MQTT discovery message (essential for Home Assistant auto-discovery) the RETAIN flag ensures that the device is still available after Home Assistant reboots.

]]>https://community.m5stack.com/topic/3235/mqtt-core-support-for-retainRSS for NodeWed, 29 Apr 2026 19:12:10 GMTWed, 28 Apr 2021 01:19:12 GMT60<![CDATA[Reply to [MQTT-Core] Support for RETAIN on Sun, 07 Dec 2025 11:30:21 GMT]]>Hello @magister

in the mean time you could try and copy the correct Python statement into an Execute mpy code block. You can find it under System.

Thanks
Felix

]]>https://community.m5stack.com/post/30285https://community.m5stack.com/post/30285Sun, 07 Dec 2025 11:30:21 GMT<![CDATA[Reply to [MQTT-Core] Support for RETAIN on Sat, 06 Dec 2025 22:16:03 GMT]]>You can edit the UIFlow2 python code to add "retain=True" as that functionality is available in the python library. What is needed is that retain= needs to be exposed in the Block definitions. Otherwise, I'm constantly having to add that back in every time I turn off editing mode.

]]>https://community.m5stack.com/post/30284https://community.m5stack.com/post/30284Sat, 06 Dec 2025 22:16:03 GMT<![CDATA[Reply to [MQTT-Core] Support for RETAIN on Tue, 23 Nov 2021 11:50:24 GMT]]>The MQTT Adafruit forum told me: "An automatic process in order to synchronize the subscriber without any data loss?
You can - please see this documentation about retained values here:
[https://io.adafruit.com/api/docs/mqtt.html#retained-values](link url) “

Checking the Github I've found an open issue about support of the MQTT retain Flag in M5 UIFlow code. See: [https://github.com/m5stack/UIFlow-Code/issues/1](link url)

My PAHO subscriber client currently displays a zero value in the retain flag returned from the M5 publisher and Adafruit broker. Do you know the status of this issue?

]]>https://community.m5stack.com/post/15572https://community.m5stack.com/post/15572Tue, 23 Nov 2021 11:50:24 GMT<![CDATA[Reply to [MQTT-Core] Support for RETAIN on Mon, 11 Oct 2021 15:51:42 GMT]]>I need it too, in UIFlow.

]]>https://community.m5stack.com/post/15099https://community.m5stack.com/post/15099Mon, 11 Oct 2021 15:51:42 GMT<![CDATA[Reply to [MQTT-Core] Support for RETAIN on Fri, 03 Sep 2021 14:23:59 GMT]]>https://community.m5stack.com/topic/1595/mqtt-subscribes-on-uiflow

]]>https://community.m5stack.com/post/14796https://community.m5stack.com/post/14796Fri, 03 Sep 2021 14:23:59 GMT<![CDATA[Reply to [MQTT-Core] Support for RETAIN on Fri, 03 Sep 2021 14:11:20 GMT]]>What all have you tried and are you using uiFlow or Arduino?

I'm pretty sure they implemented it a while back, as I originally requested it more than a year ago. I haven't tested it recently, but I believe it was working before. Let me do some digging and I'll see what I can come up with.

]]>https://community.m5stack.com/post/14795https://community.m5stack.com/post/14795Fri, 03 Sep 2021 14:11:20 GMT<![CDATA[Reply to [MQTT-Core] Support for RETAIN on Fri, 03 Sep 2021 01:03:52 GMT]]>Hi: Is there an update to this request? It seems to me that this would be very easy fix ... just adding the 'retain flag' parameter to mqtt messages. This is a very essential feature for mqtt auto-discovery with remote clients (such as Home Assistant). Without retain, Home Assistant loses all the configuration details about the M5Stack device after every HA reboot. The M5stack becomes 'unavailable' to HA and it's only after rebooting M5Stack that the device becomes available again.

]]>https://community.m5stack.com/post/14789https://community.m5stack.com/post/14789Fri, 03 Sep 2021 01:03:52 GMT