ossl_connect_step3() increments an SSL session handle reference counter on
  each call. When sessions are re-used this reference counter may be
  incremented many times, but it will be decremented only once when done (by
  Curl_ossl_session_free()); and the internal OpenSSL data will not be freed
  if this reference count remains positive. When a session is re-used the
  reference counter should be corrected by explicitly calling
  SSL_SESSION_free() after each consecutive SSL_get1_session() to avoid
  introducing a memory leak.

  (http://curl.haxx.se/bug/view.cgi?id=2926284)

  name resolves when c-ares is used for resolving.

  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.

  headers work correctly even on FreeBSD systems before v8.

  available.

  detects and uses proxies based on the environment variables. If the proxy
  was given as an explicit option it worked, but due to the setup order
  mistake proxies would not be used fine for a few protocols when picked up
  from '[protocol]_proxy'. Obviously this broke after 7.19.4. I now also added
  test case 1106 that verifies this functionality.

  (http://curl.haxx.se/bug/view.cgi?id=2913886)

  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)

  accessing alredy freed memory and thus crash when using HTTPS (with
  OpenSSL), multi interface and the CURLOPT_DEBUGFUNCTION and a certain order
  of cleaning things up. I fixed it.

  (http://curl.haxx.se/bug/view.cgi?id=2891591)

  with unknown size. Previously it was only used for posts with a known size
  larger than 1024 bytes.

  curl_easy_setopt with CURLOPT_HTTPHEADER, the library should set
  data->state.expect100header accordingly - the current code (in 7.19.7 at
  least) doesn't handle this properly. Martin Storsjo provided the fix!

  rework patch that now integrates TFTP properly into libcurl so that it can
  be used non-blocking with the multi interface and more. BLKSIZE also works.

  The --tftp-blksize option was added to allow setting the TFTP BLKSIZE from
  the command line.

  finer granularity control when generating src and lib makefiles.

  though it failed to write a very small download to disk (done in a single
  fwrite call). It turned out to be because fwrite() returned success, but
  there was insufficient error-checking for the fclose() call which tricked
  curl to believe things were fine.

  closed by libcurl before the SSL lib were shutdown and they may write to its
  socket. Detected to at least happen with OpenSSL builds.

  CURLOPT_HTTPPROXYTUNNEL enabled over a proxy, a subsequent request using the
  same proxy with the tunnel option disabled would still wrongly re-use that
  previous connection and the outcome would only be badness.

  end up with entries that wouldn't time-out:

  1. Set up a first web server that redirects (307) to a http://server:port
     that's down
  2. Have curl connect to the first web server using curl multi

  After the curl_easy_cleanup call, there will be curl dns entries hanging
  around with in_use != 0.

  (http://curl.haxx.se/bug/view.cgi?id=2891591)

  its pkg-config file.  So -Wl stuff ended up in the .pc file, which is really
  bad, and breaks if there are multiple -Wl in our LDFLAGS (which are in
  PTXdist). bug #2893592 (http://curl.haxx.se/bug/view.cgi?id=2893592)

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

  --with-nss is set but not "yes".

  I think we can still improve that to check for pkg-config in that path etc,
  but at least this patch brings back the same functionality we had before.

  the client certificate. It also disable the key name test as some engines
  can select a private key/cert automatically (When there is only one key
  and/or certificate on the hardware device used by the engine)

- Constantine Sapuntzakis provided the fix that ensures that an SSL connection
  won't be reused unless protection level for peer and host verification match.

  and GNU GSS installed due to a missing mutual exclusion of header files in
  the Kerberos 5 code path. He also verified that my patch worked for him.

  (http://curl.haxx.se/bug/view.cgi?id=2891595) which identified how an entry
  in the DNS cache would linger too long if the request that added it was in
  use that long. He also provided the patch that now makes libcurl capable of
  still doing a request while the DNS hash entry may get timed out.

  used during the FTP connection phase (after the actual TCP connect), while
  it of course should be. I also made the speed check get called correctly so
  that really slow servers will trigger that properly too.

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

  wrong percentage for small files, most notable for <1000 bytes and could
  easily end up showing more than 100% at the end. It also didn't show any
  percentage, transfer size or estimated transfer times when transferring
  less than 100 bytes.

  CURLINFO_SIZE_DOWNLOAD (the -w variable size_download) didn't work when
  getting data from ldap!

  download was 0 bytes, as libcurl would then return the size as unknown (-1)
  and not 0. I wrote a fix and test case 566 to verify it.