Changes with nginx 1.19.3 29 Sep 2020
*) Feature: the ngx_stream_set_module.
*) Feature: the "proxy_cookie_flags" directive.
*) Feature: the "userid_flags" directive.
*) Bugfix: the "stale-if-error" cache control extension was erroneously applied if backend returned a response with status code 500, 502, 503, 504, 403, 404, or 429.
*) Bugfix: "[crit] cache file ... has too long header" messages might appear in logs if caching was used and the backend returned responses with the "Vary" header line.
*) Workaround: "[crit] SSL_write() failed" messages might appear in logs when using OpenSSL 1.1.1.
*) Bugfix: "SSL_shutdown() failed (SSL: ... bad write retry)" messages might appear in logs; the bug had appeared in 1.19.2.
*) Bugfix: a segmentation fault might occur in a worker process when using HTTP/2 if errors with code 400 were redirected to a proxied location using the "error_page" directive.
*) Bugfix: socket leak when using HTTP/2 and subrequests in the njs module.