ISO has assigned two new country codes for Serbia and Montenegro.
Serbia : RS,SRB,688 (FIPS : RB)
Montenegro : ME,MNE,499 (FIPS :MJ)
Link : ISO Press Release
The country code ‘CS’ previously used for Serbia and Montenegro is now obsolete and the geonames database has been updated with the new country codes. For most records we could use the administration code 1 for the update, for 255 remaining records we have used the country code of the closest records with either ME or RS.