Hi,

I assume you mean the RequestHeader returnDiagnostics (https://reference.opcfoundation.org/v104/Core/docs/Part4/7.28/)?

In short yes, but seeing any might be harder.
Our SDK does support some OPC UA Diagnostics and in the case of SimulationServer they are by default enabled as the application is a test server.
However, for you to see anything via the request header parameter, something has to basically fail first. And we do not return diagnostics for all failure cases (e.g. some may be expected per the OPC UA spec). And in practice we of course try to fix all cases that would result in a failure (e.g. typical java stuff like NPEs etc.).

Maybe we can add some “always fails” nodes in the future etc. for testing purposes that would return the diagnostics.