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.r4 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: 0.1.0 extensions: {} class: extension kind: complex-type url: http://hl7.org/fhir/StructureDefinition/artifact-date base: http://hl7.org/fhir/StructureDefinition/Extension version: 0.1.0 required: [valueDateTime, value]