Ignition MQTT UDT question/issue

I have en edge instance with an MQTT transmitter and a full Ignition Instance running with the Distributor and the Engine modules. Everything seems to be configured right and I can see the tags under the Engine tags:

I also have the setting “Publish UDT definitions in BIRTH” in the edge transmitter:

However, I see no UDTs on the Engine side. Is there a setting or a step I’m missing to be able to use the UDTs in the Engine?

You will likely need to remove your existing tags in MQTT Engine and then Refresh from MQTT Transmission in order to have it create fresh tags from the UDT definitions. It is designed to avoid stomping your settings that you might have configured in your MQTT Engine tags (such as history, etc); therefore, you have to consciously wipe the slate clean if you want a different structure (UDTs instead of folders/primitive tags).

Thanks, what about the UDTs themselves? Should they show up in the Engine, or do I have to import them somehow?
The problem I have is that the UDT Tags show up, but there are no UDT definitions in the Engine, so I cannot access the tag’s information

They should show up when they’ve been published from the Transmission side (and it seems that you’ve correctly enabled the publishing of UDT definitions with BIRTH). Are you using the latest (4.0.7 at time of writing) versions of the modules? If not, that might be a good first step…

Yes I have the latest version installed in both the edge and the Main Ignition instance.

Engine UDTs is empty:

Edge UDTs are defined:


Anything of note in the logger? Especially after you do a [MQTT Transmission]Transmission Control/Refresh?

This is what I get after a `[MQTT Transmission]Transmission Control/Refresh:

This is what i see on the edge:

I also noticed this error:

Update: I noticed I was using Ignition 8.1.7 and the MQTT model was listed only under 8.1.5, after downgrading to 8.1.5 now the UDTs show up in the Designer.