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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

RFC 2088

> IMAP4 non-synchronizing literals

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

> Note

> See the comment behind RFC 6352 below.

RFC 2426

> vCard MIME Directory Profile

> Note

> See the comment behind RFC 6352 below.

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

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

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

RFC 5173

> Sieve Email Filtering: Body Extension

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 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 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

> Note

> See the comment behind RFC 6352 below.

RFC 6352

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

> Note

> Cyrus IMAP accepts over CardDAV both vCard 3.0 and vCard 4.0, but does not advertise over CARDDAV:supported-address-data vCard 4.0 support, announces only vCard 3.0. Moreover, Cyrus IMAP does not convert between vCard 3.0 and vCard 4.0. It is applications’ responsibility not to misinterpret the vCard version and damage the data.

RFC 6376

> DomainKeys Identified Mail (DKIM) Signatures

RFC 6558

> Sieve Extension for Converting Messages before Delivery

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 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 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 7804

> Salted Challenge Response HTTP Authentication Mechanism

RFC 7808

> Time Zone Data Distribution Service

RFC 7809

> CalDAV: Time Zones by Reference

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 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 8478

> Zstandard Compression and the application/zstd Media Type

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

## IETF RFC Drafts

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-martin-sieve-notify

> Sieve – An extension for providing instant notifications

draft-york-vpoll

> VPOLL: Consensus Scheduling Component for iCalendar

draft-desruisseaux-ischedule

> Internet Calendar Scheduling Protocol (iSchedule)

draft-gondwana-sieve-mailboxid

> Sieve Email Filtering: delivery by mailboxid

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 5182

> IMAP Extension for Referencing the Last SEARCH Result

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 5465

> The IMAP NOTIFY Extension

RFC 5466

> IMAP4 Extension for Named Searches (Filters)

RFC 5550

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

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 6901

> JavaScript Object Notation (JSON) Pointer

RFC 7162

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

RFC 7377

> IMAP4 Multimailbox SEARCH Extension

RFC 7725

> An HTTP Status Code to Report Legal Obstacles

RFC 7888

> IMAP4 Non-synchronizing Literals

RFC 7889

> The IMAP APPENDLIMIT Extension

RFC 8288

> Web Linking

RFC 8470

> Using Early Data in HTTP

RFC 8474

> IMAP Extension for Object Identifiers

> Note

> This is implemented as draft-ietf-extra-imap-objectid.

RFC 8508

> IMAP REPLACE Extension

RFC 8514

> Internet Message Access Protocol (IMAP) - SAVEDATE Extension

> Note

> This is implemented as draft-ietf-extra-imap-savedate.

RFC 8621

> The JSON Meta Application Protocol (JMAP) for Mail