This EventTypeis used by a Serverto indicate that a significant change has occurred in the Serveror in the subsystem below the Serverthat may or does invalidate the Conditionstate of a Subscription. Its representation in the AddressSpaceis formally defined in Table 135.

Table 135– RefreshRequiredEventType definition

Attribute	Value
BrowseName	RefreshRequiredEventType
IsAbstract	True
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the SystemEventTypedefined in 10000-5, i.e. it has HasProperty Referencesto the same Nodes.
ConformanceUnits
A & C Refresh
A & C Refresh2

When a Serverdetects an Eventqueue overflow, it shall track if any Condition Events have been lost, if any Condition Events were lost, it shall issue a RefreshRequiredEventType Eventto the Clientafter the Eventqueue is no longer in an overflow state.