It seems FTPCaller uses these ciphers on SFTP:
aes256-cbc,rijndael-cbc@lysator.liu.se,aes192-cbc,aes128-cbc,arcfour128,arcfour,3des-cbc
However some of these are insecure and not recommended to use and therefore not possible to use on newer ssh2-servers. Supported ciphers currently is:
chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc

