Internet Standard
Documents submitted to the IETF editor and accepted as an RFC are not revised; if the document has to be changed, it is submitted again and assigned a new RFC number. When an RFC becomes an Internet Standard (STD), it is assigned an STD number but retains its RFC number. When an Internet Standard is updated, its number is unchanged but refers to a different RFC or set of RFCs. For example, in 2007 RFC 3700 was an Internet Standard (STD 1) and in May 2008 it was replaced with RFC 5000. RFC 3700 received "Historic" status, and RFC 5000 became STD 1.