RFCs Supported by Cyrus IMAP¶
The following is an inventory of RFCs supported by Cyrus IMAP.
Standard for the format of ARPA Internet text messages, obsoleted by RFC 2822.
Network News Transfer Protocol
Standard for interchange of USENET messages
Interactive Mail Access Protocol: Version 2
Representation of Non-ASCII Text in Internet Message Headers
SMTP Service Extension for 8bit-MIMEtransport
SMTP Service Extensions
SMTP Service Extension for Message Size Declaration
Post Office Protocol - Version 3 (POP3)
DEFLATE Compressed Data Format Specification version 1.3
GZIP file format specification version 4.3
Local Mail Transfer Protocol
SMTP Service Extension for Returning Enhanced Error Codes
Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies
Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types
MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII Text
Internet Message Access Protocol - Version 4rev1, obsoleted by RFC 3501.
IMAP4 ACL Extension, obsoleted by RFC 4314.
Note
Backwards compatibility with this RFC is to be obsoleted.
IMAP4 QUOTA extension, obsoleted by RFC 9208.
IMAP4 non-synchronizing literals, obsoleted by RFC 7888.
IMAP4 IDLE command
IMAP URL Scheme, obsoleted by RFC 5092.
IMAP4 Mailbox Referrals
IMAP/POP AUTHorize Extension for Simple Challenge/Response
The TLS Protocol Version 1.0
Extensible Message Format for Message Disposition Notifications (MDNs)
IMAP4 Namespace
IMAP4 UIDPLUS extension, obsoleted by RFC 4315
A MIME Content-Type for Directory Information
vCard MIME Directory Profile
The One-Time-Password SASL Mechanism
POP3 Extension Mechanism
HTTP Extensions for Distributed Authoring -- WEBDAV
Using TLS with IMAP, POP3 and ACAP
HTTP Upgrading to TLS Within HTTP/1.1
Simple Mail Transfer Protocol
Internet Message Format
SMTP Service Extension for Command Pipelining
IMAP4 ID extension
Common NNTP Extensions
Sieve: A Mail Filtering Language
The SYS and AUTH POP Response Codes
SMTP Service Extension for Secure SMTP over TLS
Versioning Extensions to WebDAV (Web Distributed Authoring and Versioning)
Date and Time on the Internet: Timestamps
IMAP4 Child Mailbox Extension
Sieve Extension: Relational Tests
Enhanced Mail System Status Codes
Internet Message Access Protocol - version 4rev1, obsoleted by RFC 9051.
IMAP MULTIAPPEND extension
IMAP4 Binary Content Extension
Sieve Email Filtering -- Subaddress Extension, obsoleted by RFC 5233.
MUPDATE Protocol (For Cyrus Murder)
Internet Message Access Protocol (IMAP) UNSELECT command
Web Distributed Authoring and Versioning (WebDAV) Access Control Protocol
Recommendations for Automatic Responses to Electronic Mail
ESMTP and LMTP Transmission Types Registration
Sieve Extension: Copying Without Side Effects
Network News Transfer Protocol (NNTP)
The Atom Syndication Format
IMAP4 Access Control List (ACL) Extension
Internet Message Access Protocol (IMAP) - UIDPLUS extension
Quota and Size Properties for Distributed Authoring and Versioning (DAV) Collections
The Transport Layer Security (TLS) Protocol Version 1.1
Simple Authentication and Security Layer (SASL)
Collected Extensions to IMAP4 ABNF
Internet Message Access Protocol (IMAP) - URLAUTH Extension, updated by RFC 5092.
Internet Message Access Protocol (IMAP) CATENATE Extension
Anonymous Simple Authentication and Security Layer (SASL) Mechanism
Internet Email to Support Diverse Service Environments (Lemonade) Profile, obsoleted by RFC 5550.
IMAP Extension for Conditional STORE Operation or Quick Flag Changes Resynchronization, obsoleted by RFC 7162.
SPNEGO-based Kerberos and NTLM HTTP Authentication in Microsoft Windows
The PLAIN Simple Authentication and Security Layer (SASL) Mechanism
Using Transport Layer Security (TLS) with Network News Transfer Protocol (NNTP)
Network News Transfer Protocol (NNTP) Extension for Authentication
Network News Transfer Protocol (NNTP) Extension for Streaming Feeds
IMAP4 Extension to SEARCH Command for Controlling What Kind of Information Is Returned
Calendaring Extensions to WebDAV (CalDAV)
HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV)
SMTP Service Extension for Authentication
IMAP Extension for Simple Authentication and Security Layer (SASL) Initial Client Response
The IMAP COMPRESS Extension
WITHIN Search Extension to the IMAP Protocol
The Post Office Protocol (POP3) Simple Authentication and Security Layer (SASL) Authentication Mechanism
IMAP URL Scheme, updated by RFC 5593.
i;unicode-casemap - Simple Unicode Collation Algorithm
Note
This collation is ONLY supported by Sieve. Support in IMAP is documented in RFC 5255, which is currently NOT implemented.
The IMAP ENABLE Extension
IMAP4 Extensions for Quick Mailbox Resynchronization, obsoleted by RFC 7162.
Sieve Email Filtering: Body Extension
IMAP Extension for Referencing the Last SEARCH Result
Sieve Email Filtering: Environment Extension
Sieve: A Mail Filtering Language
Sieve Email Filtering: Variables Extension
Sieve Email Filtering: Vacation Extension
Sieve Email Filtering: Relational Extension
Sieve Email Filtering: Imap4flags Extension
New in version 2.5.0.
Sieve Email Filtering: Subaddress Extension
Internet Message Access Protocol - SORT and THREAD Extensions
Internet Message Access Protocol - ANNOTATE Extension
Internet Message Access Protocol version 4 - LIST Command Extensions
Sieve Email Filtering: Date and Index Extensions
New in version 2.5.0.
Contexts for IMAP4
Note
The ESORT capability is implemented. The CONTEXT=SEARCH and CONTEXT=SORT capabilities are not implemented.
Sieve Email Filtering: Editheader Extension
Simple Mail Transfer Protocol
Internet Message Format
Note
The JMAP mapping is incomplete.
WebDAV Current Principal Extension
Internet Message Store Events
Sieve Email Filtering: Reject and Extended Reject Extensions
Sieve Email Filtering: Extension for Notifications
Sieve Notification Mechanism: mailto
Sieve Email Filtering: Ihave Extension
The IMAP METADATA Extension
The IMAP NOTIFY Extension
The Sieve Mail-Filtering Language -- Extensions for Checking Mailbox Status and Accessing Mailbox Metadata
Extended URLFETCH for Binary and Converted Parts
Netnews Article Format
Netnews Architecture and Protocols
Internet Calendaring and Scheduling Core Object Specification (iCalendar)
iCalendar Transport-Independent Interoperability Protocol (iTIP)
The Internet Email to Support Diverse Service Environments (Lemonade) Profile
Note
The URL-PARTIAL capability is implemented. The CONTEXT=SEARCH, CONTEXT=SORT, CONVERT, and I18NLEVEL=1 capabilities are not implemented.
Internet Message Access Protocol (IMAP) - URL Access Identifier Extension
Extended MKCOL for Web Distributed Authoring and Versioning (WebDAV)
A protocol for Remotely Managing Sieve Scripts
IMAP4 Extension for Returning STATUS Information in Extended LIST
Display-Based Address Sorting for the IMAP4 SORT Extension
Using POST to Add Members to Web Distributed Authoring and Versioning (WebDAV) Collections
Sieve Email Filtering: Delivery Status Notifications and Deliver-By Extensions
Note
envelope-dsn and envelope-deliverby are implemented. redirect-dsn and redirect-deliverby are not implemented.
iCalendar Message-Based Interoperability Protocol (iMIP)
The Secure Sockets Layer (SSL) Protocol Version 3.0
Note
SSLv3 is considered insecure as it is vulnerable to POODLE.
Support for SSLv3 is being deprecated and removed.
Sieve Vacation Extension: "Seconds" Parameter
Sieve Extension: Externally Stored Lists
IMAP LIST Extension for Special-Use Mailboxes
Note
The unextended LIST and LSUB commands return the special-use flags, unless the
specialusealwaysconfiguration variable is explicitly turned off.
IMAP4 Extension for Fuzzy Search
xCal: The XML Format for iCalendar
vCard Format Specification
CardDAV: vCard Extensions to Web Distributed Authoring and Versioning (WebDAV)
DomainKeys Identified Mail (DKIM) Signatures
The WebSocket Protocol
Collection Synchronization for Web Distributed Authoring and Versioning (WebDAV)
Additional HTTP Status Codes
Sieve Email Filtering: Include Extension
Scheduling Extensions to CalDAV
Locating Services for Calendaring Extensions to WebDAV (CalDAV) and vCard Extensions to WebDAV (CardDAV)
HTTP Strict Transport Security (HSTS)
Internet Message Access Protocol (IMAP) - MOVE Extension
New in version 2.5.0.
IMAP Support for UTF-8
Note
This extension will only be advertised and supported if both 'reject8bit' and 'munge8bit' are disabled.
JavaScript Object Notation (JSON) Pointer
IMAP Extensions: Quick Flag Changes Resynchronization (CONDSTORE) and Quick Mailbox Resynchronization (QRESYNC)
Forwarded HTTP Extension
Prefer Header for HTTP
jCal: The JSON Format for iCalendar
Sieve Email Filtering: Detecting Duplicate Deliveries
IMAP4 Multimailbox SEARCH Extension
Non-Gregorian Recurrence Rules in the Internet Calendaring and Scheduling Core Object Specification (iCalendar)
HTTP Authentication-Info and Proxy-Authentication-Info Response Header Fields, obsoleted by RFC 9110
The 'Basic' HTTP Authentication Scheme
Compression Extensions for WebSocket
Hypertext Transfer Protocol (HTTP) Client-Initiated Content-Encoding, obsoleted by RFC 9110
An HTTP Status Code to Report Legal Obstacles
Salted Challenge Response HTTP Authentication Mechanism
Time Zone Data Distribution Service
CalDAV: Time Zones by Reference
IMAP4 Non-synchronizing Literals
The IMAP APPENDLIMIT Extension
Brotli Compressed Data Format
Calendar Availability
New Properties for iCalendar
Note
Support here means, that when the iCalendar stream is retrieved with HTTP GET, Cyrus IMAP inserts the color, description and name from the WebDAV properties. IMAGE, SOURCE, multi-lingual calendar DESCRIPTIONs, URL, LAST-MODIFIED, CATEGORIES, and REFRESH-INTERVAL are not exported on iCalendar streams retrieved with GET.
Individual iCalendar objects (VEVENT, VTODO, VJOURNAL) can be uploaded and downloaded with the New Properties for iCalendar.
Use of the Prefer Header Field in Web Distributed Authoring and Versioning (WebDAV)
HTTP Immutable Responses
Web Linking
An HTTP Status Code for Indicating Hints
IMAP UNAUTHENTICATE Extension for Connection Reuse
IMAP Extension for STATUS=SIZE
IMAP4 Extension for Returning MYRIGHTS Information in Extended LIST
Bootstrapping WebSockets with HTTP/2
IMAP "$Important" Keyword and "Important" Special-Use Attribute
IMAP Extension for Object Identifiers
IMAP REPLACE Extension
Internet Message Access Protocol (IMAP) - SAVEDATE Extension
Sieve Email Filtering: Delivering to Special-Use Mailboxes
Sieve Extension: File Carbon Copy (FCC)
Calendaring Extensions to WebDAV (CalDAV): Managed Attachments
The JSON Meta Application Protocol (JMAP)
Note
The PushSubscription object and its methods are not yet supported.
The JSON Meta Application Protocol (JMAP) for Mail
Zstandard Compression and the application/zstd Media Type
A JSON Meta Application Protocol (JMAP) Subprotocol for WebSocket
IMAP4 Extension: Message Preview Generation
Sieve Email Filtering: Delivery by MAILBOXID
Internet Message Access Protocol (IMAP) - version 4rev2
HTTP Semantics
HTTP Caching
HTTP/1.1
HTTP/2
IMAP QUOTA Extension
IMAP PARTIAL Extension for Paged SEARCH and FETCH
JSON Meta Application Protocol (JMAP) Blob Management Extension
JSON Meta Application Protocol (JMAP) for Quotas
JSContact: A JSON Representation of Contact Data
vCard Format Extensions for JSContact
JSContact: Converting from and to vCard
IMAP4 Response Code for Command Progress Notifications
IMAP Extension for Using and Returning Unique Identifiers (UIDs) Only
IMAP4 Extension for Returning Mailbox METADATA in Extended LIST
The JSON Meta Application Protocol (JMAP) for Sieve Scripts
Sieve Email Filtering: Extension for Processing Calendar Attachments
IETF RFC Drafts¶
draft-ietf-extra-jmapaccess
The JMAPACCESS Extension for IMAP
draft-ietf-extra-sieve-snooze
Sieve Email Filtering: Snooze Extension
draft-ietf-sieve-regex
Sieve Email Filtering -- Regular Expression Extension
draft-ietf-calext-vpoll
VPOLL: Consensus Scheduling Component for iCalendar
draft-ietf-jmap-calendars
JMAP for Calendars
draft-ietf-jmap-contacts
JMAP for Contacts
draft-ietf-jmap-sharing
JMAP Sharing
draft-murchison-lmtp-ignorequota
LMTP Service Extension for Ignoring Recipient Quotas
draft-desruisseaux-ischedule
Internet Calendar Scheduling Protocol (iSchedule)
draft-thomson-hybi-http-timeout
Hypertext Transfer Protocol (HTTP) Keep-Alive Header
caldav-ctag Calendar Collection Entity Tag (CTag) in CalDAV Brief Header Microsoft 'Brief' header extension
RFC Wishlist¶
IMAP4 Login Referrals
Transparent Content Negotiation in HTTP
The Use of URLs as Meta-Syntax for Core Mail List Commands and their Transport through Message Header Fields
Delta encoding in HTTP
Sieve Email Filtering: Spamtest and Virustest Extensions
Internet Message Access Protocol Internationalization
Internet Message Access Protocol - CONVERT Extension
Sieve Notification Mechanism: Extensible Messaging and Presence Protocol (XMPP)
IMAP4 Extension for Named Searches (Filters)
Sieve Email Filtering: MIME Part Tests, Iteration, Extraction, Replacement, and Enclosure
Binding Extensions to Web Distributed Authoring and Versioning (WebDAV)
Sieve Notification Mechanism: SIP MESSAGE
Sieve Extension for Converting Messages before Delivery
Support for Internet Message Access Protocol (IMAP) Events in Sieve
Using Early Data in HTTP