from the help section in WS FTP....
Preserving file date and time

By default, when you transfer files, the file date and time are updated to the date and time of the transfer. You can change this, so that the date and time are preserved.

To set how date and time are handled:

From the Site Manager, select the site in the Sites list.

Click the Edit  button.

Select the Transfer page.

Select or clear Preserve filetime on uploads or Preserve filetime on downloads.

Important Note about Uploads

If the preservation of file date and time is not supported by the FTP site, you will get an "MTDM" error when you upload files to the site. Note, however, that the files will transfer correctly with updated timestamps from the FTP site. (The "MTDM" error is not serious, even though it displays in red.)

kind regards, Paul C. Beugeling