Changes with nginx 1.21.5 28 Dec 2021
*) Change: now nginx is built with the PCRE2 library by default.
*) Change: now nginx always uses sendfile(SF_NODISKIO) on FreeBSD.
*) Feature: support for sendfile(SF_NOCACHE) on FreeBSD.
*) Feature: the $ssl_curve variable.
*) Bugfix: connections might hang when using HTTP/2 without SSL with the
“sendfile” and “aio” directives.
转自 https://nginx.org/en/download.html