If events are supported, the root node of the specific interface (e.g. IMM_MES_Interface for OPC 40077) shall set the SubscribeToEventsflag in the EventNotifierattribute.

If event history is supported, the root node of the specific interface (e.g. IMM_MES_Interface for OPC 40077) shall set the HistoryReadflag in the EventNotifierattribute.