FHIR Versions

The FHIR specification is under active development. The latest version, R5, was officially published in March 2023. Major updates to the FHIR specification are typically published every few years, and minor updates are published more frequently.

Major updates to FHIR can have breaking changes, but typically these changes only occur in areas of the specification that are not fully mature. FHIR uses a maturity model that describes “the level of stability and implementation readiness associated with different aspects of the specification.”

For example, the Patient resource was assigned a “normative” maturity level in the R4 release of FHIR. This means that starting in the R4 release, the content of the Patient resource

is considered to be stable and has been ‘locked’, subjecting it to FHIR Inter-version Compatibility Rules. While changes are possible, they are expected to be infrequent and are tightly constrained. (source)

Other resources, like NutritionProduct have a much lower maturity level even in the R5 release. These resources are likely to experience more significant changes – including breaking changes – in subsequent releases of FHIR.

Implications for this website

References to resources and examples on this website typically use the Patient or Observation. Like Patient, Observation was “normative” as of FHIR R4, so the release of FHIR R5 and future versions is unlikely to affect these examples.

To ensure consistency between content in this website and links to the FHIR specification (or FHIR Implementation Guides), we link to version-specific pages whenever quoting from a specification or referencing material that might change in a future version. For example, we would link to the version-independent URL when generally referencing the Patient resource (https://www.hl7.org/fhir/patient.html), but would link to the R4 URL when stating that Patient achieved “normative” maturity in R4 ((https://www.hl7.org/fhir/R4/patient.html)). More details are in the Style Guide.

Due to these mitigation approaches, the content on this website should be relatively unaffected by new releases of the FHIR specification. However, if updates do need to be made, anyone is welcome to contribute.