Added async server‑side copy: SITE CPFR/CPTO/COPY.
Added recursive size DSIZ and recursive delete RMDA (plus SITE RMDIR).
Added free‑space reporting: AVBL and XQUOTA.
Added SITE UMASK and SITE SYMLINK; fixed SITE CHMOD.
Expanded FEAT/MLST support and improved list/data transfer behavior.
Added version/build info to the FTP banner.
Some clients (e.g. WinSCP) can be configured to use these extra commands for file management operations.