RFC 6857: Post-Delivery Message Downgrading for Internationalized Email Messages

The Email Address Internationalization (SMTPUTF8) extension to SMTP allows Unicode characters encoded in UTF-8 and outside the ASCII repertoire in mail header…

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Outgoing relationships (12 related RFCs)

Normative reference — RFC 2119: Key words for use in RFCs to Indicate Requirement Levels
Normative reference — RFC 5890: Internationalized Domain Names for Applications (IDNA): Definitions and Document Framework
Normative reference — RFC 5891: Internationalized Domain Names in Applications (IDNA): Protocol
Normative reference — RFC 2183: Communicating Presentation Information in Internet Messages: The Content-Disposition Header Field
Normative reference — RFC 2231: MIME Parameter Value and Encoded Word Extensions: Character Sets, Languages, and Continuations
Normative reference — RFC 6531: SMTP Extension for Internationalized Email
Normative reference — RFC 4021: Registration of Mail and MIME Header Fields
Normative reference — RFC 6855: IMAP Support for UTF-8
Normative reference — RFC 6856: Post Office Protocol Version 3 (POP3) Support for UTF-8
Informative reference — RFC 5234: Augmented BNF for Syntax Specifications: ABNF
Informative reference — RFC 5451: Message Header Field for Indicating Message Authentication Status
Informative reference — RFC 5504: Downgrading Mechanism for Email Address Internationalization

Incoming relationships (3 related RFCs)

Normatively referenced by — RFC 6855: IMAP Support for UTF-8
Informatively referenced by — RFC 6858: Simplified POP and IMAP Downgrading for Internationalized Email
Informatively referenced by — RFC 9698: The JMAPACCESS Extension for IMAP