Fixed background update with "if". Cloned subrequests should inherit r->content_handler. This way they will be able to use the same location configuration as the original request if there are "if" directives in the configuration. Without r->content_handler inherited, the following configuration tries to access a static file in the update request: location / { set $true 1; if ($true) { # nothing } proxy_pass http://backend; proxy_cache one; proxy_cache_use_stale updating; proxy_cache_background_update on; } See http://mailman.nginx.org/pipermail/nginx/2017-February/053019.html for initial report.