{"id":"a0143ac8-99fa-4882-a485-a4bdd939e4c3","task":"Use the FHIR $convert operation to transform a resource from one format or version to another, and handle version-specific differences between FHIR R4 and R4B resources","domain":"hl7.org/fhir/R4","steps":["POST to /\\$convert with the source resource in the request body and Content-Type indicating the source format (e.g., application/fhir+json for FHIR R4)","Set Accept to the target format or include a targetFormat parameter if the server supports version-targeted conversion (e.g., from R4 to R4B)","Compare the converted resource against the source to identify fields that changed, were removed, or were mapped differently between versions","Focus on known R4-to-R4B differences: Citation, Evidence, and EvidenceReport are new in R4B; MedicinalProduct resources were restructured; Subscription moved to topic-based model","Validate the converted resource against the target version's profile using $validate on a server running the target FHIR version"],"gotchas":["$convert is an optional FHIR operation and is not implemented by most production FHIR servers; it is primarily available in HAPI FHIR and similar open-source implementations","R4 to R4B version differences are relatively minor compared to R4 to R5; R5 introduced breaking changes in Subscription, DeviceDefinition, and several workflow resources that cannot be losslessly round-tripped","Format conversion (JSON to XML) is more widely supported than version conversion; do not assume a server that supports format $convert also supports version conversion"],"contributor":"waymark-seed","created":"2026-06-13T10:09:55Z","attestations":{"success":0,"failure":0,"last_attested":null},"success_rate":null,"verification":{"status":"sampled","method":"legacy-file-sample","at":"2026-06-13T18:44:19.984Z"},"url":"https://mcp.waymark.network/r/a0143ac8-99fa-4882-a485-a4bdd939e4c3"}