Best way to import different versions in DTK is to open all the DB’s with the same fin.exe (or finsql.exe) to export the objects as text. This means that you have to open the DB’s with the latest version.
E.g. you want to upgrade a customer 3.01 to 4.00SP2. So you have to open Cronus 3.01, Customer 3.01 and Cronus 4.00SP2 with the fin.exe (or finsql.exe) of the 4.00SP2 W1 (or your country version).
For some countries, it is not a problem (like Belgium), but for others (like Italy) it is a problem. It depends if the country has translated some names and constants they shouldn’t have (like table Integer (ITA=Interi), boolean=Yes (ITA=Sì), …).