4.3 Earlier bad letter detection
4.4 REST for large files
4.5 ASCII support
+ 4.6 GSSAPI via Windows SSPI
5. HTTP
5.1 Better persistency for HTTP 1.0
FTP ASCII transfers do not follow RFC959. They don't convert the data
accordingly.
+4.6 GSSAPI via Windows SSPI
+
+In addition to currently supporting the SASL GSSAPI mechanism (Kerberos V5)
+via third-party GSS-API libraries, such as Heimdal or MIT Kerberos, also add
+support for Kerberos via Windows SSPI.
+
5. HTTP
5.1 Better persistency for HTTP 1.0