MimeKit implements the following IETF specifications defining Internet Mail and MIME:
- 0822: Standard for the Format of Arpa Internet Text Messages
- 1341: MIME (Multipurpose Internet Mail Extensions): Mechanisms for Specifying and Describing the Format of Internet Message Bodies
- 1342: Representation of Non-ASCII Text in Internet Message Headers
- 1521: MIME (Multipurpose Internet Mail Extensions) Part One: Mechanisms for Specifying and Describing the Format of Internet Message Bodies (Obsoletes rfc1341)
- 1522: MIME (Multipurpose Internet Mail Extensions) Part Two: Message Header Extensions for Non-ASCII Text (Obsoletes rfc1342)
- 1544: The Content-MD5 Header Field
- 1847: Security Multiparts for MIME: Multipart/Signed and Multipart/Encrypted
- 1864: The Content-MD5 Header Field (Obsoletes rfc1544)
- 1872: The MIME Multipart/Related Content-type
- 1892: The Multipart/Report Content Type for the Reporting of Mail System Administrative Messages
- 2015: MIME Security with Pretty Good Privacy (PGP)
- 2045: Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies
- 2046: Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types
- 2047: Multipurpose Internet Mail Extensions (MIME) Part Three: Message Header Extensions for Non-ASCII Text
- 2048: Multipurpose Internet Mail Extensions (MIME) Part Four: Registration Procedures
- 2049: Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance Criteria and Examples
- 2110: MIME E-mail Encapsulation of Aggregate Documents, such as HTML (MHTML)
- 2111: Content-ID and Message-ID Uniform Resource Locators
- 2112: The MIME Multipart/Related Content-type (Obsoletes rfc1872)
- 2183: Communicating Presentation Information in Internet Messages: The Content-Disposition Header Field
- 2184: MIME Parameter Value and Encoded Word Extensions: Character Sets, Languages, and Continuations
- 2231: MIME Parameter Value and Encoded Word Extensions: Character Sets, Languages, and Continuations (Obsoletes rfc2184)
- 2298: An Extensible Message Format for Message Disposition Notifications
- 2311: S/MIME Version 2 Message Specification
- 2312: S/MIME Version 2 Certificate Handling
- 2315: PKCS #7: Cryptographic Message Syntax
- 2387: The MIME Multipart/Related Content-type (Obsoletes rfc2112)
- 2424: Content Duration MIME Header Definition
- 2557: MIME Encapsulation of Aggregate Documents, such as HTML (MHTML) (Obsoletes rfc2110)
- 2630: Cryptographic Message Syntax
- 2632: S/MIME Version 3 Certificate Handling
- 2633: S/MIME Version 3 Message Specification
- 2634: Enhanced Security Services for S/MIME
- 2822: Internet Message Format (Obsoletes rfc0822)
- 3156: MIME Security with OpenPGP (Updates rfc2015)
- 3462: The Multipart/Report Media Type for the Reporting of Mail System Administrative Messages (Obsoletes rfc1892)
- 3464: An Extensible Message Format for Delivery Status Notifications
- 3798: Message Disposition Notification (Obsoletes rfc2298)
- 3850: S/MIME Version 3.1 Certificate Handling (Obsoletes rfc2632)
- 3851: S/MIME Version 3.1 Message Specification (Obsoletes rfc2633)
- 4262: X.509 Certificate Extension for S/MIME Capabilities
- 4871: DomainKeys Identified Mail (DKIM) Signatures
- 5322: Internet Message Format (Obsoletes rfc2822)
- 5451: Message Header Field for Indicating Message Authentication Status
- 5672: RFC 4871 DomainKeys Identified Mail (DKIM) Signatures -- Update
- 5750: S/MIME Version 3.2 Certificate Handling (Obsoletes rfc3850)
- 5751: S/MIME Version 3.2 Message Specification (Obsoletes rfc3851)
- 6376: DomainKeys Identified Mail (DKIM) Signatures (Obsoletes rfc4871)
- 6522: The Multipart/Report Media Type for the Reporting of Mail System Administrative Messages (Obsoletes rfc3462)
- 6532: Internationalized Email Headers
- 6533: Internationalized Delivery Status and Disposition Notifications
- 7001: Message Header Field for Indicating Message Authentication Status (Obsoletes rfc5451)
- 7601: Message Header Field for Indicating Message Authentication Status (Obsoletes rfc7001)
- 8301: Cryptographic Algorithm and Key Usage Update to DomainKeys Identified Mail (DKIM)
- 8463: A New Cryptographic Signature Method for DomainKeys Identified Mail (DKIM)
- 1523: The text/enriched MIME Content-type
- 1927: Suggested Additional MIME Types for Associating Documents
- 2369: The Use of URLs as Meta-Syntax for Core Mail List Commands and their Transport through Message Header Fields
- 2388: Returning Values from Forms: multipart/form-data
- 6577: Authentication-Results Registration Update for Sender Policy Framework (SPF) Results
- 7103: Advice for Safe Handling of Malformed Messages
- 7410: A Property Types Registry for the Authentication-Results Header Field
- 8550: S/MIME Version 4.0 Certificate Handling (Obsoletes rfc5750)
- 8551: S/MIME Version 4.0 Message Specification (Obsoletes rfc5751)