* is older than Privoxy's error message, the server would send status code
* 304 and the browser would display the outdated error message again and again.
*
- * For documents delivered with status code 403, 404 and 503 we set "Last-Modified"
- * to Tim Berners-Lee's birthday, which predates the age of any page on the web
- * and can be safely used to "revalidate" without getting a status code 304.
+ * For documents delivered with status code 403, 404, 502, 503 and
+ * 504 we set "Last-Modified" to Tim Berners-Lee's birthday, which
+ * predates the age of any page on the web and can be safely used to
+ * "revalidate" without getting a status code 304.
*
* There is no need to let the useless If-Modified-Since header reach the
* server, it is therefore stripped by client_if_modified_since in parsers.c.