It seems the NAV 2009 to 2015 upgrade routine misses transferring the “County” (state) data into the new field.In NAV2009 the field number is 28000 and in NAV2015 it becomes 5

The data migration step 1 is there, the data is copied into a temp copy of the Post Code, just it’s not copied back.

Add in the following code in for to work properly

// >> JIG
IF TempPostCode.FINDSET THEN
    REPEAT
        IF PostCode.GET(TempPostCode.Code, TempPostCode.City) THEN BEGIN
            PostCode.County := TempPostCode.County;
            PostCode.MODIFY;
        END;
        
        TempPostCode.DELETE;
    UNTIL TemPostCode.NEXT;
// << JIG