This is the Continuous Integration Build of FHIR (will be incorrect/inconsistent at times). 
See the Directory of published versions 
| Infrastructure And Messaging  Work Group | Maturity Level: 4 | Trial Use | Compartments: Device, Practitioner | 
Dependency Graph for MessageHeader FMM level 4
| Name | Card. | Type | Dependency Analysis | 
|---|---|---|---|
|   MessageHeader | DomainResource | ||
|    event[x] | 1..1 | ||
|     eventCoding | Coding | ||
|     eventUri | uri | ||
|     eventCanonical | canonical | ||
|    destination | 0..* | BackboneElement | |
|     endpoint[x] | 0..1 | ||
|      endpointUrl | url | ||
|      endpointReference | Reference(Endpoint | Type Warning: (Endpoint = FMM2-Trial Use vs. Element = FMM4-Trial Use) | |
|     name | 0..1 | string | |
|     receiver | 0..1 | Reference(Device | Organization | Patient | Practitioner | PractitionerRole | RelatedPerson) | Type Warning: (Device = FMM2-Trial Use vs. Element = FMM4-Trial Use) | 
|    source | 1..1 | BackboneElement | |
|     endpoint[x] | 0..1 | ||
|      endpointUrl | url | ||
|      endpointReference | Reference(Endpoint | Type Warning: (Endpoint = FMM2-Trial Use vs. Element = FMM4-Trial Use) | |
|     name | 0..1 | string | |
|     software | 0..1 | string | |
|     version | 0..1 | string | |
|     contact | 0..1 | ContactPoint | |
|     sender | 0..1 | Reference(Device | Organization | Patient | Practitioner | PractitionerRole) | Type Warning: (Device = FMM2-Trial Use vs. Element = FMM4-Trial Use) | 
|    reason | 0..1 | CodeableConcept | |
|    response | 0..1 | BackboneElement | |
|     identifier | 1..1 | Identifier | |
|     code | 1..1 | code | |
|     details | 0..1 | Reference(OperationOutcome) | |
|    focus | 0..* | Reference(Any) | Type Warning: (Any = FMM1-Trial Use vs. Element = FMM4-Trial Use) | 
|    definition | 0..1 | canonical(MessageDefinition) | Type Warning: (MessageDefinition = FMM1-Trial Use vs. Element = FMM4-Trial Use) |