description: This cross-version extension represents MessageHeader.response.identifier from http://hl7.org/fhir/StructureDefinition/MessageHeader|4.0.1 for use in FHIR R5. package_name: hl7.fhir.uv.xver-r4.r5 derivation: constraint name: Ext_R4_MessageHeader_re_identifier type: Extension elements: url: base: {max: '1', min: 1, path: Extension.url} pattern: {type: Uri, value: 'http://hl7.org/fhir/4.0/StructureDefinition/extension-MessageHeader.response.identifier'} index: 0 value: base: {max: '1', min: 0, path: 'Extension.value[x]'} short: Id of original message choices: [valueId] index: 2 valueId: base: {max: '1', min: 0, path: 'Extension.value[x]'} type: id short: Id of original message choiceOf: value index: 3 package_version: 0.0.1-snapshot-2 class: extension kind: complex-type url: http://hl7.org/fhir/4.0/StructureDefinition/extension-MessageHeader.response.identifier base: http://hl7.org/fhir/StructureDefinition/Extension|5.0.0 version: 0.0.1-snapshot-2 required: [url]