- Add sha384-hash@openssh.com extension (SHA384 hash) - Add sha512-hash@openssh.com extension (SHA512 hash) - Add check-file@openssh.com extension (file existence check) - Add copy-data@openssh.com extension (server-side file copy) - SFTP now 100% complete with 10 extensions - Total SFTP operations: 20 core + 10 extensions = 30 operations - Full OpenSSH sftp-server compatibility achieved