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MQTT Engine Custom Namespaces, configured to parse the payload as JSON, do not handle changing JSON structures automatically due to the way JSON payloads are parsed.

Consider these two examples of changing payloads on the same topic:

(1) Two message payloads received sequential sequentially on topic "a/b" at MQTT Engine where payload 2 has a modified element from message 1:

{
    "level": "value1"
}

{
    "level": {
        "key": "value2"
    }
}

...

Now, when the second payload arrives on the same topic, since MQTT Engine does not automatically delete tags, it will try to create the tag "[MQTT Engine]a/b/level/key" with a value of 'value2'. However, level at this point is a leaf tag, not a folder. So, the new leaf tag called 'key' can not be created.

(2) Two message payloads received sequentially on topic "a/b" at MQTT Engine where message 2 is a subset of message 1:

{
    "level": "low"
	"temp": "45.0"
	"alarm": "on"
}

At this point, MQTT Engine will create multiple tags with the tagpaths of:

• "[MQTT Engine]a/b/level" with a value of 'low'
• "[MQTT Engine]a/b/temp" with a value of '45.0'
• "[MQTT Engine]a/b/alarm" with a value of 'on'

{
    "level": "high"
	"temp": "99.0"
}

On the arrival of the second message, the two leaf tags 'level' and 'temp' will be updated so all tags will now look as follows:

• "[MQTT Engine]a/b/level" with a value of 'high'
• "[MQTT Engine]a/b/temp" with a value of '99.0'
• "[MQTT Engine]a/b/alarm" with a value of 'on'

When the second payload arrives on the same topic, since MQTT Engine does not automatically delete tags, it will not modify the tag "[MQTT Engine]a/b/alarm". It will remain as 'good' quality as well.

...