Nginx 0.7.21 版本发布了，新版本主要修正了一些bug，同时也有引入新特性，详细信息如下：
Changes with nginx 0.7.21
*) Changes in the ngx_http_limit_req_module.
*) Feature: the EXSLT support in the ngx_http_xslt_module.
*) Workaround: compatibility with glibc 2.3.
*) Bugfix: nginx could not run on MacOSX 10.4 and earlier; the bug had appeared in 0.7.6.
Changes with nginx 0.7.20
*) Changes in the ngx_http_gzip_filter_module.
*) Feature: the ngx_http_limit_req_module.
*) Bugfix: worker processes might exit on a SIGBUS signal on sparc and ppc platforms; the bug had appeared in 0.7.3.
*) Bugfix: the "proxy_pass http://host/some:uri" directives did not work; the bug had appeared in 0.7.12.
*) Bugfix: in HTTPS mode requests might fail with the "bad write retry" error.
*) Bugfix: the ngx_http_secure_link_module did not work inside locations, whose names are less than 3 characters.
*) Bugfix: $server_addr variable might have no value.