http://hl7.org/fhir/StructureDefinition/valueset-expirationDate|4.0.1

The date when the value set version is no longer expected to be used to create new content. This is the first date-time when the value set version becomes Inactive, so this value SHALL present on all Inactive value set versions. The start Date_time is expected to be as of 0001 UTC of the Expiration Date.
NameFlagsCardTypeDescription & Constraints
Extension
0..1When the value set version should no longer be used
 
extension
?..0
 
url
?..?
 
value[x] *
1..?
 
 
valueDate *
1..?date