Linux is an OS, not an FTP/SFTP file manager, you can know what kind of mta server you're using by entering the server and looking at the welcome message (something like "Connected! MTA SA Server 1.5 [GNU/Linux]", the red part says which OS you're using for running your server), if you're paying a server hoster, then you are probably using Windows, if you're using a VPS, then Linux, but check it out, also you can know it if you're running your MTA Server from an exe file (Windows) or a archive with no extension (Linux).
I'm paying for host now how to update it?