Changes with nginx 1.7.11 24 Mar 2015

    *) Change: the "sendfile" parameter of the "aio" directive is
       deprecated; now nginx automatically uses AIO to pre-load data for
       sendfile if both "aio" and "sendfile" directives are used.

    *) Feature: experimental thread pools support.

    *) Feature: the "proxy_request_buffering", "fastcgi_request_buffering",
       "scgi_request_buffering", and "uwsgi_request_buffering" directives.

    *) Feature: request body filters experimental API.

    *) Feature: client SSL certificates support in mail proxy.
       Thanks to Sven Peter, Franck Levionnois, and Filipe Da Silva.

    *) Feature: startup speedup when using the "hash ... consistent"
       directive in the upstream block.
       Thanks to Wai Keen Woon.

    *) Feature: debug logging into a cyclic memory buffer.

    *) Bugfix: in hash table handling.
       Thanks to Chris West.

    *) Bugfix: in the "proxy_cache_revalidate" directive.

    *) Bugfix: SSL connections might hang if deferred accept or the
       "proxy_protocol" parameter of the "listen" directive were used.
       Thanks to James Hamlin.

    *) Bugfix: the $upstream_response_time variable might contain a wrong
       value if the "image_filter" directive was used.

    *) Bugfix: in integer overflow handling.
       Thanks to Régis Leroy.

    *) Bugfix: it was not possible to enable SSLv3 with LibreSSL.

    *) Bugfix: the "ignoring stale global SSL error ... called a function
       you should not call" alerts appeared in logs when using LibreSSL.

    *) Bugfix: certificates specified by the "ssl_client_certificate" and
       "ssl_trusted_certificate" directives were inadvertently used to
       automatically construct certificate chains.