Changes with nginx 1.9.15 19 Apr 2016
*) Bugfix: "recv() failed" errors might occur when using HHVM as a FastCGI server.
*) Bugfix: when using HTTP/2 and the "limit_req" or "auth_request" directives a timeout or a "client violated flow control" error might occur while reading client request body; the bug had appeared in 1.9.14.
*) Workaround: a response might not be shown by some browsers if HTTP/2 was used and client request body was not fully read; the bug had appeared in 1.9.14.
*) Bugfix: connections might hang when using the "aio threads" directive. Thanks to Mindaugas Rasiukevicius.