versions --ftp-ssl and --ftp-ssl-reqd as these options are now used to
  control SSL/TLS for IMAP, POP3 and SMTP as well in addition to FTP. The old
  option names are still working but the new ones are the prefered ones
  (listed and documented).

  command is a special "hack" used by the drftpd server, but even though it is
  a custom extension I've deemed it fine to add to libcurl since this server
  seems to survive and people keep using it and want libcurl to support
  it. The new libcurl option is named CURLOPT_FTP_USE_PRET, and it is also
  usable from the curl tool with --ftp-pret. Using this option on a server
  that doesn't support this command will make libcurl fail.

  on FTP errors in the transient 5xx range. Transient FTP errors are in the
  4xx range. The code itself only tried on 5xx errors that occured _at login_.
  Now the retry code retries on all FTP transfer failures that ended with a
  4xx response.

  (http://curl.haxx.se/bug/view.cgi?id=2911279)

  instead of being repeated several times. This also include Authenticate: and
  Proxy-Authenticate: headers and while this hardly every happens in real life
  it will confuse libcurl which does not properly support it for all headers -
  like those Authenticate headers.

have been fixed!

Added '--configure' option to curl-config to display original configure arguments when curl was built

curl.h, adjusting auto-makefiles include path, to enhance portability to
OS's without an orthogonal directory tree structure such as OS/400.

and another is sponsoring more

As it actually builds with gcrypt these days, but not the NSS functions.