According to the documentation “outputOrgUnitIdScheme” is a valid parameter for the Analytics endpoint however I am not able to get Codes returned.
See here for reproduction on Play. I would expect to see the value of “orgUnit” to be OU_539
as the Code shows here: https://play.dhis2.org/2.35.7/api/organisationUnits/YuQRtpLP10I.json