receptionist_rollback_incompatible
The chosen healthy version would make a current answering-policy location selector, runtime route, or direct-handoff target unsafe. Update the policy or choose another compatible version.
Problem shape
Every non-2xx response is an RFC 9457 application/problem+json body. The type URI below is stable and machine-matchable, so branch on the final path segment (the code) and treat the status as redundant confirmation. See the error-handling guide.
{
"type": "https://docs.vocapable.com/errors/receptionist_rollback_incompatible",
"title": "…",
"status": 409,
"detail": "…",
"instance": "/v1/…"
}