description: The date (and optionally time) when the {{title}} was last significantly changed. The date must change when the business version changes and it must change if the status code changes. In addition, it should change when the substantive content of the {{title}} changes. package_name: hl7.fhir.uv.extensions derivation: constraint name: ArtifactDate type: Extension elements: extension: {index: 0} url: pattern: {type: Uri, value: 'http://hl7.org/fhir/StructureDefinition/artifact-date'} index: 1 value: choices: [valueDateTime] index: 3 valueDateTime: {type: dateTime, choiceOf: value, index: 4} package_version: 5.1.0-snapshot1 extensions: {} class: extension kind: complex-type url: http://hl7.org/fhir/StructureDefinition/artifact-date base: http://hl7.org/fhir/StructureDefinition/Extension version: 5.1.0-snapshot1 required: [valueDateTime, value]