Editing Simple Mail Transfer Protocol (section)

===Internationalization extension===
{{Main|International email}}

Original SMTP supports email addresses composed of [[ASCII]] characters only, which is inconvenient for users whose native script is not Latin based, or who use [[diacritic]] not in the ASCII character set. This limitation was alleviated via extensions enabling UTF-8 in address names. {{IETF RFC|5336|}} introduced experimental<ref name=parms/> <code>UTF8SMTP</code> command and later was superseded by {{IETF RFC|6531|}} that introduced <code>SMTPUTF8</code> command. These extensions provide support for multi-byte and non-ASCII characters in email addresses, such as those with diacritics and other language characters such as [[Greek language|Greek]] and [[Chinese language|Chinese]].<ref>{{cite mailing list|url=http://www.ietf.org/mail-archive/web/ima/current/msg05395.html|title=Chinese email address|date=19 December 2014|access-date=24 May 2016|mailing-list=EAI|author=Jiankang Yao|publisher=[[Internet Engineering Task Force|IETF]]|archive-date=October 2, 2015|archive-url=https://web.archive.org/web/20151002170118/http://www.ietf.org/mail-archive/web/ima/current/msg05395.html|url-status=live}}</ref>

Current support is limited, but there is strong interest in broad adoption of {{IETF RFC|6531}} and the related RFCs in countries like [[China]] that have a large user base where Latin (ASCII) is a foreign script.