A FHIR conversation requires agreement on the FHIR version before exchange.

• A. True
• B. False
• C. Not necessarily
• D. Always

Answer: (A)

Two systems exchanging FHIR data must operate on the same FHIR version because each version defines different resource structures, element availability, and semantics. If the sender uses one version and the receiver expects another, resources can be misinterpreted or fail validation, leading to incompatible exchanges. In practice, you indicate the version via the versioned base URL (for example, baseR4 or baseDSTU2) and verify support through the server’s CapabilityStatement, which lists the versions it supports. Some servers can handle multiple versions, but the interaction should still explicitly agree on which version to use to ensure consistent interpretation and operations.