Nginx 1.15.3 官方更新日志：
http://nginx.org/en/CHANGES

Changes with nginx 1.15.3                                        28 Aug 2018

    *) Feature: now TLSv1.3 can be used with BoringSSL.

    *) Feature: the "ssl_early_data" directive, currently available with
       BoringSSL.

    *) Feature: the "keepalive_timeout" and "keepalive_requests" directives
       in the "upstream" block.

    *) Bugfix: the ngx_http_dav_module did not truncate destination file
       when copying a file over an existing one with the COPY method.

    *) Bugfix: the ngx_http_dav_module used zero access rights on the
       destination file and did not preserve file modification time when
       moving a file between different file systems with the MOVE method.

    *) Bugfix: the ngx_http_dav_module used default access rights when
       copying a file with the COPY method.

    *) Workaround: some clients might not work when using HTTP/2; the bug
       had appeared in 1.13.5.

    *) Bugfix: nginx could not be built with LibreSSL 2.8.0.