nginx 0.8.53 *) Feature: now the "error_page" directive allows to change a status code in a redirect. *) Feature: the "gzip_disable" directive supports special "degradation" mask. *) Bugfix: a socket leak might occurred if file AIO was used. Thanks to Maxim Dounin. *) Bugfix: if the first server had no "listen" directive and there was no explicit default server, then a next server with a "listen" directive became the default server; the bug had appeared in 0.8.21.

--- a/src/http/ngx_http.h
+++ b/src/http/ngx_http.h
@@ -142,6 +142,10 @@ char *ngx_http_merge_types(ngx_conf_t *c
 ngx_int_t ngx_http_set_default_types(ngx_conf_t *cf, ngx_array_t **types,
     ngx_str_t *default_type);
 
+#if (NGX_HTTP_DEGRADATION)
+ngx_uint_t  ngx_http_degraded(ngx_http_request_t *);
+#endif
+
 
 extern ngx_module_t  ngx_http_module;