description: The Message Header Instruction extension is provided to carry a specific instruction for receivers of the message. package_name: fhir.r4.ukcore.stu3.currentbuild derivation: constraint name: ExtensionUKCoreMessageHeaderInstruction type: Extension elements: url: pattern: {type: uri, value: 'https://fhir.hl7.org.uk/StructureDefinition/Extension-UKCore-MessageHeaderInstruction'} type: uri index: 0 value: short: The Instruction for receivers of the message. choices: [valueCoding] index: 2 valueCoding: {type: Coding, short: The Instruction for receivers of the message., choiceOf: value, index: 3} package_version: 0.0.8-pre-release class: extension kind: complex-type url: https://fhir.hl7.org.uk/StructureDefinition/Extension-UKCore-MessageHeaderInstruction base: http://hl7.org/fhir/StructureDefinition/Extension version: 1.0.0 required: [value, valueCoding]