FTP Client - Overwrite a folder (removing orphaned files)

Solution 1:

Imo, there's nothing like "overwriting a folder", in general. And definitely not in FTP.

What you want to achieve is called directory/folder synchronization.

Some FTP clients do support synchronizing local and remote folders.

• WinSCP does:
  https://winscp.net/eng/docs/ui_synchronize
  You will want to enable Delete files option to get rid of obsolete files (aaa.txt in your example).

• Cyberduck too:
  https://docs.cyberduck.io/cyberduck/sync/
  Though it seems it does not support deleting obsolete files, so it's probably not useful for your purposes.

• FileZilla imo does not. I do not know about WS_FTP.