For what it's worth regarding transferring contacts from an old email program/client to a new email program/client, this is what I do...
Using Excel or a spreadsheet program that handles CSV files. Using the old Contact List, EXPORT the contacts to a .csv file. Rename the file old_contacts.csv. This is your current contact list but to IMPORT it into the new email program/client, the columns and headings of the spreadsheet csv need to be what it is expecting and the original one you exported will not necessarily be exactly what the new program is expecting.
To know what the new program expects and make a new reordered list that can be inported, the first step is to go to the new email program and export those contacts to a different .csv file. If the program doesn't have contacts yet, add yourself as a new contact. Then export the contact list as a csv and rename the file new_contacts.csv. If you open the new spreadsheet, you will see the spreadsheet list the way that your new email programs likes it to look - even though there may be only one line, one contact with your information.
Keep the new one open and open the old one. Now you can copy columns from the old list into the new list using spreadsheet Copy and Past skills and omitting the column names of course. Once you get the columns containing the First, Last, Email, etc copied in to the new spreadsheet, save it.
Now you have a csv file (new_contacts.csv) formatted/ordered that will work with your new email program's contact list. Now you can IMPORT this list you made.