Better yet, use the DX4WIN Data Updater to update the file.
After you download the correct ZIP archive, extract DX4WIN.MAS or DX4WIN.MAS1 file to your DX4W### directory (not the SAVE directory). Changes won't appear until you restart DX4WIN.
For more information on creating/using master callsign databases in DX4WIN, please read this Application Note.
This membership list for DX4WIN 8.01 and later contains LoTW, eQSL and OQRS (Online QSL Request Service) The list of LoTW users comes from an unofficial list maintained by Robert, HB9BZA. The list of eQSL users contains only stations that have Authenticity Guaranteed status, in other words, they are good for CQ and/or eQSL awards. The list of OQRS users comes from an unofficial list maintained by David, KJ4IZW.
When a member of one of these lists is spotted on the DX Cluster, one or more identifying letters may appear in the Memb column of the DX spots window:
After you download the ZIP archive, extract DX4WIN.MAS2 to your DX4W### directory (not the SAVE directory). Changes won't appear until you restart DX4WIN.