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# Cyrus IMAP

# RFCs Supported by Cyrus IMAP

The following is an inventory of RFCs supported by Cyrus IMAP.

RFC 822

> Standard for the format of ARPA Internet text messages, obsoleted by RFC 2822.

RFC 0977

> Network News Transfer Protocol

RFC 1036

> Standard for interchange of USENET messages

RFC 1176

> Interactive Mail Access Protocol: Version 2

RFC 1342

> Representation of Non-ASCII Text in Internet Message Headers

RFC 1652

> SMTP Service Extension for 8bit-MIMEtransport

RFC 1730

> Internet Message Access Protocol - version 4, obsoleted by RFC 2060, RFC 2061, RFC 3501.

RFC 1869

> SMTP Service Extensions

RFC 1870

> SMTP Service Extension for Message Size Declaration

RFC 1939

> Post Office Protocol - Version 3 (POP3)

RFC 1951

> DEFLATE Compressed Data Format Specification version 1.3

RFC 1952

> GZIP file format specification version 4.3

RFC 2033

> Local Mail Transfer Protocol

RFC 2034

> SMTP Service Extension for Returning Enhanced Error Codes

RFC 2045

> Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies

RFC 2046

> Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types

RFC 2047

> MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII Text

RFC 2060

> Internet Message Access Protocol - Version 4rev1, obsoleted by RFC 3501.

RFC 2086

> IMAP4 ACL Extension, obsoleted by RFC 4314.

> Note

> Backwards compatibility with this RFC is to be obsoleted.

RFC 2087

> IMAP4 QUOTA extension, obsoleted by RFC 9208.

RFC 2088

> IMAP4 non-synchronizing literals, obsoleted by RFC 7888.

RFC 2177

> IMAP4 IDLE command

RFC 2192

> IMAP URL Scheme, obsoleted by RFC 5092.

RFC 2193

> IMAP4 Mailbox Referrals

RFC 2195

> IMAP/POP AUTHorize Extension for Simple Challenge/Response

RFC 2246

> The TLS Protocol Version 1.0

RFC 2298

> Extensible Message Format for Message Disposition Notifications (MDNs)

RFC 2342

> IMAP4 Namespace

RFC 2359

> IMAP4 UIDPLUS extension, obsoleted by RFC 4315

RFC 2425

> A MIME Content-Type for Directory Information

RFC 2426

> vCard MIME Directory Profile

RFC 2444

> The One-Time-Password SASL Mechanism

RFC 2449

> POP3 Extension Mechanism

RFC 2518

> HTTP Extensions for Distributed Authoring -- WEBDAV

RFC 2595

> Using TLS with IMAP, POP3 and ACAP

RFC 2617

> HTTP Authentication: Basic and Digest Access Authentication, updated by RFC 7615, RFC 7616, RFC 7617.

RFC 2817

> HTTP Upgrading to TLS Within HTTP/1.1

RFC 2818

> HTTP Over TLS

RFC 2821

> Simple Mail Transfer Protocol

RFC 2822

> Internet Message Format

RFC 2831

> Using Digest Authentication as a SASL Mechanism

RFC 2920

> SMTP Service Extension for Command Pipelining

RFC 2971

> IMAP4 ID extension

RFC 2980

> Common NNTP Extensions

RFC 3028

> Sieve: A Mail Filtering Language

RFC 3206

> The SYS and AUTH POP Response Codes

RFC 3207

> SMTP Service Extension for Secure SMTP over TLS

RFC 3253

> Versioning Extensions to WebDAV (Web Distributed Authoring and Versioning)

RFC 3339

> Date and Time on the Internet: Timestamps

RFC 3348

> IMAP4 Child Mailbox Extension

RFC 3431

> Sieve Extension: Relational Tests

RFC 3463

> Enhanced Mail System Status Codes

RFC 3501

> Internet Message Access Protocol - version 4rev1, obsoleted by RFC 9051.

RFC 3502

> IMAP MULTIAPPEND extension

RFC 3516

> IMAP4 Binary Content Extension

RFC 3598

> Sieve Email Filtering -- Subaddress Extension, obsoleted by RFC 5233.

RFC 3656

> MUPDATE Protocol (For Cyrus Murder)

RFC 3691

> Internet Message Access Protocol (IMAP) UNSELECT command

RFC 3744

> Web Distributed Authoring and Versioning (WebDAV) Access Control Protocol

RFC 3834

> Recommendations for Automatic Responses to Electronic Mail

RFC 3848

> ESMTP and LMTP Transmission Types Registration

RFC 3894

> Sieve Extension: Copying Without Side Effects

RFC 3977

> Network News Transfer Protocol (NNTP)

RFC 4287

> The Atom Syndication Format

RFC 4314

> IMAP4 Access Control List (ACL) Extension

RFC 4315

> Internet Message Access Protocol (IMAP) - UIDPLUS extension

RFC 4331

> Quota and Size Properties for Distributed Authoring and Versioning (DAV) Collections

RFC 4346

> The Transport Layer Security (TLS) Protocol Version 1.1

RFC 4422

> Simple Authentication and Security Layer (SASL)

RFC 4466

> Collected Extensions to IMAP4 ABNF

RFC 4467

> Internet Message Access Protocol (IMAP) - URLAUTH Extension, updated by RFC 5092.

RFC 4469

> Internet Message Access Protocol (IMAP) CATENATE Extension

RFC 4505

> Anonymous Simple Authentication and Security Layer (SASL) Mechanism

RFC 4550

> Internet Email to Support Diverse Service Environments (Lemonade) Profile

RFC 4551

> IMAP Extension for Conditional STORE Operation or Quick Flag Changes Resynchronization, obsoleted by RFC 7162.

RFC 4559

> SPNEGO-based Kerberos and NTLM HTTP Authentication in Microsoft Windows

RFC 4616

> The PLAIN Simple Authentication and Security Layer (SASL) Mechanism

RFC 4642

> Using Transport Layer Security (TLS) with Network News Transfer Protocol (NNTP)

RFC 4643

> Network News Transfer Protocol (NNTP) Extension for Authentication

RFC 4644

> Network News Transfer Protocol (NNTP) Extension for Streaming Feeds

RFC 4731

> IMAP4 Extension to SEARCH Command for Controlling What Kind of Information Is Returned

RFC 4791

> Calendaring Extensions to WebDAV (CalDAV)

RFC 4918

> HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV)

RFC 4954

> SMTP Service Extension for Authentication

RFC 4959

> IMAP Extension for Simple Authentication and Security Layer (SASL) Initial Client Response

RFC 4978

> The IMAP COMPRESS Extension

RFC 5032

> WITHIN Search Extension to the IMAP Protocol

RFC 5034

> The Post Office Protocol (POP3) Simple Authentication and Security Layer (SASL) Authentication Mechanism

RFC 5092

> IMAP URL Scheme, updated by RFC 5593.

RFC 5161

> The IMAP ENABLE Extension

RFC 5162

> IMAP4 Extensions for Quick Mailbox Resynchronization, obsoleted by RFC 7162.

RFC 5173

> Sieve Email Filtering: Body Extension

RFC 5182

> IMAP Extension for Referencing the Last SEARCH Result

RFC 5183

> Sieve Email Filtering: Environment Extension

RFC 5228

> Sieve: A Mail Filtering Language

RFC 5229

> Sieve Email Filtering: Variables Extension

RFC 5230

> Sieve Email Filtering: Vacation Extension

RFC 5231

> Sieve Email Filtering: Relational Extension

RFC 5232

> Sieve Email Filtering: Imap4flags Extension

> New in version 2.5.0.

RFC 5233

> Sieve Email Filtering: Subaddress Extension

RFC 5235

> Sieve Email Filtering: Spamtest and Virustest Extensions

RFC 5256

> Internet Message Access Protocol - SORT and THREAD Extensions

RFC 5257

> Internet Message Access Protocol - ANNOTATE Extension

RFC 5258

> Internet Message Access Protocol version 4 - LIST Command Extensions

RFC 5260

> Sieve Email Filtering: Date and Index Extensions

> New in version 2.5.0.

RFC 5267

> Contexts for IMAP4

> Note

> The ESORT capability is implemented. The CONTEXT=SEARCH and CONTEXT=SORT capabilities are not implemented.

RFC 5293

> Sieve Email Filtering: Editheader Extension

RFC 5321

> Simple Mail Transfer Protocol

RFC 5322

> Internet Message Format

> Note

> The JMAP mapping is incomplete.

RFC 5397

> WebDAV Current Principal Extension

RFC 5423

> Internet Message Store Events

RFC 5429

> Sieve Email Filtering: Reject and Extended Reject Extensions

RFC 5435

> Sieve Email Filtering: Extension for Notifications

RFC 5436

> Sieve Notification Mechanism: mailto

RFC 5463

> Sieve Email Filtering: Ihave Extension

RFC 5464

> The IMAP METADATA Extension

RFC 5465

> The IMAP NOTIFY Extension

RFC 5490

> The Sieve Mail-Filtering Language -- Extensions for Checking Mailbox Status and Accessing Mailbox Metadata

RFC 5524

> Extended URLFETCH for Binary and Converted Parts

RFC 5536

> Netnews Article Format

RFC 5537

> Netnews Architecture and Protocols

RFC 5545

> Internet Calendaring and Scheduling Core Object Specification (iCalendar)

RFC 5546

> iCalendar Transport-Independent Interoperability Protocol (iTIP)

RFC 5550

> The Internet Email to Support Diverse Service Environments (Lemonade) Profile

> Note

> The URL-PARTIAL capability is implemented. The CONTEXT=SEARCH, CONTEXT=SORT, CONVERT, I18NLEVEL=1, and NOTIFY capabilities are not implemented.

RFC 5593

> Internet Message Access Protocol (IMAP) - URL Access Identifier Extension

RFC 5689

> Extended MKCOL for Web Distributed Authoring and Versioning (WebDAV)

RFC 5703

> Sieve Email Filtering: MIME Part Tests, Iteration, Extraction, Replacement, and Enclosure

RFC 5804

> A protocol for Remotely Managing Sieve Scripts

RFC 5819

> IMAP4 Extension for Returning STATUS Information in Extended LIST

RFC 5957

> Display-Based Address Sorting for the IMAP4 SORT Extension

RFC 5995

> Using POST to Add Members to Web Distributed Authoring and Versioning (WebDAV) Collections

RFC 6009

> Sieve Email Filtering: Delivery Status Notifications and Deliver-By Extensions

RFC 6047

> iCalendar Message-Based Interoperability Protocol (iMIP)

RFC 6101

> 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.

RFC 6131

> Sieve Vacation Extension: "Seconds" Parameter

RFC 6134

> Sieve Extension: Externally Stored Lists

RFC 6154

> IMAP LIST Extension for Special-Use Mailboxes

> Note

> The LIST and LSUB commands return the special-use flags, unless the `specialusealways` configuration variable is explicitly turned off.

RFC 6203

> IMAP4 Extension for Fuzzy Search

RFC 6321

> xCal: The XML Format for iCalendar

RFC 6350

> vCard Format Specification

RFC 6352

> CardDAV: vCard Extensions to Web Distributed Authoring and Versioning (WebDAV)

RFC 6376

> DomainKeys Identified Mail (DKIM) Signatures

RFC 6558

> Sieve Extension for Converting Messages before Delivery

RFC 6455

> The WebSocket Protocol

RFC 6578

> Collection Synchronization for Web Distributed Authoring and Versioning (WebDAV)

RFC 6585

> Additional HTTP Status Codes

RFC 6609

> Sieve Email Filtering: Include Extension

RFC 6638

> Scheduling Extensions to CalDAV

RFC 6764

> Locating Services for Calendaring Extensions to WebDAV (CalDAV) and vCard Extensions to WebDAV (CardDAV)

RFC 6797

> HTTP Strict Transport Security (HSTS)

RFC 6851

> Internet Message Access Protocol (IMAP) - MOVE Extension

> New in version 2.5.0.

RFC 6901

> JavaScript Object Notation (JSON) Pointer

RFC 7162

> IMAP Extensions: Quick Flag Changes Resynchronization (CONDSTORE) and Quick Mailbox Resynchronization (QRESYNC)

RFC 7230

> Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing

RFC 7231

> Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content

RFC 7232

> Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests

RFC 7233

> Hypertext Transfer Protocol (HTTP/1.1): Range Requests

RFC 7234

> Hypertext Transfer Protocol (HTTP/1.1): Caching

RFC 7235

> Hypertext Transfer Protocol (HTTP/1.1): Authentication

RFC 7238

> The Hypertext Transfer Protocol Status Code 308 (Permanent Redirect)

RFC 7239

> Forwarded HTTP Extension

RFC 7240

> Prefer Header for HTTP

RFC 7265

> jCal: The JSON Format for iCalendar

RFC 7352

> Sieve Email Filtering: Detecting Duplicate Deliveries

RFC 7377

> IMAP4 Multimailbox SEARCH Extension

RFC 7529

> Non-Gregorian Recurrence Rules in the Internet Calendaring and Scheduling Core Object Specification (iCalendar)

RFC 7540

> Hypertext Transfer Protocol Version 2 (HTTP/2)

RFC 7615

> HTTP Authentication-Info and Proxy-Authentication-Info Response Header Fields

RFC 7616

> HTTP Digest Access Authentication

RFC 7617

> The 'Basic' HTTP Authentication Scheme

RFC 7692

> Compression Extensions for WebSocket

RFC 7694

> Hypertext Transfer Protocol (HTTP) Client-Initiated Content-Encoding

RFC 7725

> An HTTP Status Code to Report Legal Obstacles

RFC 7804

> Salted Challenge Response HTTP Authentication Mechanism

RFC 7808

> Time Zone Data Distribution Service

RFC 7809

> CalDAV: Time Zones by Reference

RFC 7888

> IMAP4 Non-synchronizing Literals

RFC 7889

> The IMAP APPENDLIMIT Extension

RFC 7932

> Brotli Compressed Data Format

RFC 7953

> Calendar Availability

RFC 7986

> 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.

RFC 8144

> Use of the Prefer Header Field in Web Distributed Authoring and Versioning (WebDAV)

RFC 8246

> HTTP Immutable Responses

RFC 8288

> Web Linking

RFC 8297

> An HTTP Status Code for Indicating Hints

RFC 8437

> IMAP UNAUTHENTICATE Extension for Connection Reuse

RFC 8438

> IMAP Extension for STATUS=SIZE

RFC 8440

> IMAP4 Extension for Returning MYRIGHTS Information in Extended LIST

RFC 8441

> Bootstrapping WebSockets with HTTP/2

RFC 8474

> IMAP Extension for Object Identifiers

RFC 8508

> IMAP REPLACE Extension

RFC 8514

> Internet Message Access Protocol (IMAP) - SAVEDATE Extension

RFC 8579

> Sieve Email Filtering: Delivering to Special-Use Mailboxes

RFC 8580

> Sieve Extension: File Carbon Copy (FCC)

RFC 8607

> Calendaring Extensions to WebDAV (CalDAV): Managed Attachments

RFC 8620

> The JSON Meta Application Protocol (JMAP)

RFC 8621

> The JSON Meta Application Protocol (JMAP) for Mail

RFC 8878

> Zstandard Compression and the application/zstd Media Type

RFC 8887

> A JSON Meta Application Protocol (JMAP) Subprotocol for WebSocket

RFC 8970

> IMAP4 Extension: Message Preview Generation

RFC 9051

> Internet Message Access Protocol (IMAP) - version 4rev2

RFC 9208

> IMAP QUOTA Extension

## IETF RFC Drafts

draft-ietf-extra-imap-list-metadata

> IMAP4 Extension for Returning Mailbox METADATA in Extended LIST

draft-ietf-extra-sieve-mailboxid

> Sieve Email Filtering: delivery by mailboxid

draft-ietf-extra-sieve-snooze

> Sieve Email Filtering: Snooze Extension

draft-ietf-extra-imap-uidonly

> IMAP Extension for only using and returning UIDs

draft-ietf-jmap-calendars

> JMAP for Calendars

draft-ietf-jmap-sieve

> JMAP for Sieve Scripts

draft-murchison-lmtp-ignorequota

> LMTP Service Extension for Ignoring Recipient Quotas

[MS-NTHT] NTLM Over HTTP Protocol Specification

draft-ietf-sieve-regex

> Sieve Email Filtering -- Regular Expression Extension

draft-york-vpoll

> VPOLL: Consensus Scheduling Component for iCalendar

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

RFC 2221

> IMAP4 Login Referrals

RFC 2295

> Transparent Content Negotiation in HTTP

RFC 2369

> The Use of URLs as Meta-Syntax for Core Mail List Commands and their Transport through Message Header Fields

RFC 3229

> Delta encoding in HTTP

RFC 5255

> Internet Message Access Protocol Internationalization

RFC 5259

> Internet Message Access Protocol - CONVERT Extension

RFC 5437

> Sieve Notification Mechanism: Extensible Messaging and Presence Protocol (XMPP)

RFC 5466

> IMAP4 Extension for Named Searches (Filters)

RFC 5842

> Binding Extensions to Web Distributed Authoring and Versioning (WebDAV)

RFC 6468

> Sieve Notification Mechanism: SIP MESSAGE

RFC 6785

> Support for Internet Message Access Protocol (IMAP) Events in Sieve

RFC 6855

> IMAP Support for UTF-8

RFC 8470

> Using Early Data in HTTP