The Internet community generally adds features by extension, allowing communication in both directions between upgraded machines and not-yet-upgraded machines, rather than declaring formerly standards-compliant legacy software to be "broken" and insisting that all software worldwide be upgraded to the latest standard. In the mid-1990s, people[who?] objected to "just send 8 bits (to RFC 821 SMTP servers)", perhaps because of a perception that "just send 8 bits" is an implicit declaration that ISO 8859-1 become the new "standard encoding", forcing everyone in the world to use the same character set.[original research?] Instead, the recommended way to take advantage of 8-bit-clean links between machines is to use the ESMTP (RFC 1869) 8BITMIME extension[11][12] for message bodies and the SMTP SMTPUTF8[13] extension for message headers.