I would like to recommend pre-adopting the new Endpoint.environmentType element (see linked issue) in this profile, either directly or as an extension. That element is being added to FHIR R5 but isn't present in R4. For scaling directory services it is critical to automatically distinguish between various types of environments: development, test, staging, production, etc. When implementers are building an interface between two different systems they will typically start with a non-production environment before switching to the production environment. We need to prevent any misunderstandings there because if a production client application accidentally sends PHI to a non-production endpoint that could result in a privacy violation or patient safety issue.