Storage MemberID data type

Hi,

As per Storage.v1_8_0.json, MemberId is mentioned as string till Redfish v1.6, but Redfish v1.6 or higher suggest to zero-based array index.
But in Redfish 1.5, we used string value as sata_controller_0, but as per schema we need change to zero-based array index in Redfish v1.6 or higher
Can we expect type can be changed to number instead of string in schema? If it's going to be string type  can we use sata_controller_0(unique value)?
If we use string value sata_controller_0, redfish conformance tool is throwing error to use zero-based array index

"MemberId": {
"description": "The identifier for the member within the collection.",
"longDescription": "This property shall uniquely identify the member within the collection. For services supporting Redfish v1.6 or higher, this value shall contain the zero-based array index.",
"readonly": true,
"type": "string"
}

Thanks,
Mani