There is a correlation between ModelChangeEvents and the NodeVersion Property of Nodes. Every time a ModelChangeEvent is issued for a Node, its NodeVersion shall be changed, and every time the NodeVersion is changed, a ModelChangeEvent shall be generated. A Server shall support both the ModelChangeEvent and the NodeVersion Property or neither, but never only one of the two mechanisms.

This relation also implies that only those Nodes of the AddressSpace having a NodeVersion shall trigger a ModelChangeEvent. Other Nodes shall not trigger a ModelChangeEvent.