Hello, I've found a minor bug on the synchronous read. When a new group is created, the field IsSubscribed is set to True even though the read is synchronous. This is important in a case like mine where the RPC server has not the asynchronous read available, the execution caused an exception due to the absence of RPC server. I suggest moving the line to the "if not sync:" statement two lines after. Basically, from: if new_group: opc_group.IsSubscribed = 1 opc_group.IsActive = 1 if not sync: if self.trace:...