codes than RFC 2616 (HTTP/1.1), which came 3 years later. 402 (Payment required), 206 (Partial content), etc all introduced later, and are safe for existing clients only because of the above defensive specification. RFC 1945: HTTP status codes are extensible[...]. HTTP applications are not required to understand the meaning of all registered status codes[...]. However, applications must understand the class of any status code, as indicated by the first digit, and treat any unrecognized response as being equivalent to the x00 status code of that class, with the exception that an unrecognized response must not be cached. Deliver Your Software in an Envelope http://localhost:8080/print/ 51 of 59 4/13/14, 12:57 PM