We have a coreftp sftp server running on Windows. FlashFXP fails to correctly detect that it only handles regular codepage based filenames.
If i send files with danish characters in them they end up mangled on the server. Filezilla manages to detect it correctly.
The CoreFtp server was recently rewritten and most internals were rewritten to be unicode but apparently that didn't help the unicode for clients transferring files
But regardless. FlashFXP's auto detection is broken, so that should be fixed.