Hello,

I have checked the source code, in order to get the precise picture. Here is how it works:

* FixedLayoutPubSubConnection (FixedLayoutGroup): For all writers, KeyFrameCount is applied only when the transport uses JSON (not for UADP).
* FlexibleLayoutPubSubConnection (FlexibleLayoutGroup): For all writers, KeyFrameCount is applied only when the transport uses JSON (not for UADP).
* DynamicLayoutPubSubConnection (DynamicLayoutGroup): For all writers, KeyFrameCount is applied (both with JSON and UADP).

There were some reasons to do it this way; they had to do with the fact that the design of the writer groups/dataset writers comes from an initial OPC UA PubSub PlugFest, where it was/is required from the participants to use certain settings (there was some freedom, and that's we we tried to capture with the configurable options, but some settings were mandatory). I am hesitant to make a change to the UADemoPublisher that would not be backward compatible. But, if you describe to me what is it that you are trying to achieve/test, perhaps I could add something to allow that, in a compatible way.

Best regards