I see that a controller (ClinicalDiagnosisController) is involved, which means patient JSON is affected, shouldn't controller be able to read old JSONs which still use ORPHA instead of ORDO? I guess we don't need a migration since internally (not in JSON) we don't store the prefix? In any case, isn't this a large enough change to test it a lot, and not commit directly to master?
The controller was introduced in rc1, so there's no need for backwards compatibility.
I agree that the commit is pretty big and more reviews would have been nice. OTOH it is relatively innocent, as it affects exactly one component that was just introduced and that doesn't currently interact with anything other than one field in the patient form.