| 2045 | Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message BodiesN. Freed, N. Borenstein | Draft Standard | November 1996 |
| 2047 | MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII TextK. Moore | Draft Standard | November 1996 |
| 2119 | Key words for use in RFCs to Indicate Requirement LevelsS. Bradner | Best Current Practice | March 1997 |
| 2183 | Communicating Presentation Information in Internet Messages: The Content-Disposition Header FieldR. Troost, S. Dorner, K. Moore, Ed. | Proposed Standard | August 1997 |
| 2231 | MIME Parameter Value and Encoded Word Extensions: Character Sets, Languages, and ContinuationsN. Freed, K. Moore | Proposed Standard | November 1997 |
| 3461 | Simple Mail Transfer Protocol (SMTP) Service Extension for Delivery Status Notifications (DSNs)K. Moore | Draft Standard | January 2003 |
| 3629 | UTF-8, a transformation format of ISO 10646F. Yergeau | Internet Standard | November 2003 |
| 3864 | Registration Procedures for Message Header FieldsG. Klyne, M. Nottingham, J. Mogul | Best Current Practice | September 2004 |
| 4021 | Registration of Mail and MIME Header FieldsG. Klyne, J. Palme | Proposed Standard | March 2005 |
| 5234 | Augmented BNF for Syntax Specifications: ABNFD. Crocker, Ed., P. Overell | Internet Standard | January 2008 |
| 5322 | Internet Message FormatP. Resnick, Ed. | Draft Standard | October 2008 |
| 5451 | Message Header Field for Indicating Message Authentication StatusM. Kucherawy · obsoleted by RFC 7001 | Proposed Standard | April 2009 |
| 5504 | Downgrading Mechanism for Email Address InternationalizationK. Fujiwara, Ed., Y. Yoneya, Ed. · obsoleted by RFC 6530 | Experimental | March 2009 |
| 5741 | RFC Streams, Headers, and BoilerplatesL. Daigle, Ed., O. Kolkman, Ed., IAB · obsoleted by RFC 7841 | Informational | December 2009 |
| 5890 | Internationalized Domain Names for Applications (IDNA): Definitions and Document FrameworkJ. Klensin | Proposed Standard | August 2010 |
| 5891 | Internationalized Domain Names in Applications (IDNA): ProtocolJ. Klensin | Proposed Standard | August 2010 |
| 6530 | Overview and Framework for Internationalized EmailJ. Klensin, Y. Ko | Proposed Standard | February 2012 |
| 6531 | SMTP Extension for Internationalized EmailJ. Yao, W. Mao | Proposed Standard | February 2012 |
| 6532 | Internationalized Email HeadersA. Yang, S. Steele, N. Freed | Proposed Standard | February 2012 |
| 6533 | Internationalized Delivery Status and Disposition NotificationsT. Hansen, Ed., C. Newman, A. Melnikov | Proposed Standard | February 2012 |
| 6854 | Update to Internet Message Format to Allow Group Syntax in the "From:" and "Sender:" Header FieldsB. Leiba | Proposed Standard | March 2013 |
| 6855 | IMAP Support for UTF-8P. Resnick, Ed., C. Newman, Ed., S. Shen, Ed. · obsoleted by RFC 9755 | Proposed Standard | March 2013 |
| 6856 | Post Office Protocol Version 3 (POP3) Support for UTF-8R. Gellens, C. Newman, J. Yao, K. Fujiwara | Proposed Standard | March 2013 |