So I wonder why you get such an error when you have duplicate values for the “Rank” attribute (which in my opinion is allowed).
The only thing I can imagine is that they changed the XML-Schema, which is a mortal sinn ;-).
I will try to find out whether the XML-Schema was changed.
Are you sure that you don’t have a duplicate “OrderNumber” in your codelist?
I validated my data using P21 v3.0 and got an error for DD0001 which I believe is incorrectly implemented:
Duplicate unique value [2] declared for identity constraint “UC-CL-2” of element “CodeList”.
Specifically, it is due to the attribute RANK for element EnumeratedItem not being unique among values in a code list.
When I look at the define.xml v2.0 specification it says:
Numeric significance of the EnumeratedItem relative to others in the CodeList. Business Rule: If this value is provided for any EnumeratedItem, it must be provided for all. Note that the Rank attribute does not imply a display order.
The specification normally states specifically, if a value needs to be unique so my interpretation is that RANK would not need be unique.