This specification provides the possibility to indicate changes in the AddressSpace to a client. Most often this concept is used in list representations, to add or delete Nodes from the list. OPC 10000-3 defines the property NodeVersion and the GeneralModelChangeEventType to indicate such changes. Whenever the address space in this specification is changing, the NodeVersion and the GeneralModelChangeEvent shall be used in the way defined in OPC 10000-3.

As content for the NodeVersion Property, a timestamp of the moment the node structure was changed converted to a string with the format yyyy-MM-ddTHH:mm:ss.sZ (using UTC time for display) shall be used.