IMAP Capabilities & Commands Extensions

This page provides documentation on known commands extensions and their level of support in K-9:

Capabilities

Capability Description Support RFC
IMAP4rev1 Support for modern IMAP Supported ?
ACL Access Control Lists No RFC4314
ANNOTATE-EXPERIMENT-1 Indicate the support for experimental annotations No RFC5257
APPENDLIMIT ? ? RFC7889
AUTH=PLAIN Authentication via a plain password Supported RFC 3501
AUTH=CRAM_MD5 Authentication via SASL CRAM-MD5 Supported RFC 3501
AUTH=EXTERNAL External authentication Supported RFC 3501
AUTH=XOAUTH2 Authentication via OAuth 2.0 No RFC 3501
BINARY Binary CTE support No RFC3516
CAPABILITY List available capabilities Supported N/A
CATENATE Concatenate data with existing message No RFC4469
CHILDREN Child folder mailbox command No RFC3348
COMPRESS=DEFLATE Support for using DEFLATE to compress data Supported RFC4978
CONDSTORE Conditional STORE operation No RFC7162
CONTEXT=SEARCH ? No RFC5267
CONTEXT=SORT ? No RFC5267
CONVERT ? No RFC5259
CREATE-SPECIAL-USE ? No RFC6154
ENABLE Client notification of extension support No RFC 5161
ESEARCH ? ? RFC4731
ESORT ? ? RFC5267
FILTERS ? ? RFC5466
I18NLEVEL=1 ? ? RFC5255
I18NLEVEL=2 ? ? RFC5255
ID Mail server software identification No RFC2971
IDLE Indicates the server supports IMAP IDLE Supported RFC2177
IMAPSIEVE= ? ? RFC6785
LANGUAGE ? ? RFC5255
LIST-EXTENDED ? ? RFC5258
LIST-STATUS ? ? RFC5819
LITERAL+ Allows alternative form for literals Unknown RFC7888
LITERAL- Allows alternative form for literals Unknown RFC7888
LOGIN-REFERRALS ? ? RFC2221
LOGINDISABLED ? ? RFC2595 & RFC3501
MAILBOX-REFERRALS ? ? RFC2193
METADATA ? ? RFC5464
METADATA-SERVER ? ? RFC5464
MOVE ? ? RFC6851
MULTIAPPEND ? ? RFC3502
MULTISEARCH ? ? RFC7377
NAMESPACE Support for namespaces Partial support RFC 2343
NOTIFY Request unsolicited notifications No RFC5465
QRESYNC ? ? RFC7162
QUOTA Resource usage restriction information No RFC2087
RIGHTS= ? ? RFC4314
SASL-IR Initial Client Response form of SASL authentication No RFC4959
SEARCH=FUZZY ? ? RRFC6203
SEARCHRES ? ? RRFC5182
SORT ? ? RRFC5256
SORT=DISPLAY ? ? RRFC5957
SPECIAL-USE ? ? RRFC6154
STARTTLS Support for upgrading to TLS Supported RFC2595 / RFC3501
THREAD ? ? RFC5256]
UIDPLUS UID-based responses No RFC4315
UNSELECT Closing mailboxes without expunging Unknown RFC3691
URLFETCH=BINARY ? ? RFC5524
URL-PARTIAL ? ? RFC5550
URLAUTH ? ? RFC4467
UTF8=ACCEPT ? ? RFC6855
UTF8=ALL (OBSOLETE) ? ? RFC5738 / RFC6855
UTF8=APPEND (OBSOLETE) ? ? RFC5738 / RFC6855
UTF8=ONLY ? ? RFC6855
UTF8=USER (OBSOLETE ? ? RFC5738 / RFC6855
WITHIN ? ? RFC5032
XLIST Google Mail specific deprecated list command No  
X-GM-EXT-1 Google Mail custom behaviour: No GMail

Commands

Command Description Usage
APPEND Appends the literal argument as a new message to the end of the specified destination mailbox. Yes
AUTHENTICATE Indicates a Simple Authentication and Security Layer (SASL) authentication mechanism to the server. Yes
CAPABILITY Requests a listing of capabilities that the server supports. Yes
CHECK Requests a checkpoint of the currently selected mailbox. No
CLOSE Permanently removes all messages that have the \Deleted flag set from the currently selected mailbox, and returns to the authenticated state from the selected state. No
COPY/UID COPY Copies the specified message(s) to the end of the specified destination mailbox. Yes
CREATE Creates a mailbox with the given name. Yes
DELETE Permanently removes the mailbox with the given name. No
EXAMINE Identical to SELECT and returns the same output; however, the selected mailbox is identified as read-only. Yes
EXPUNGE Permanently removes all messages that have the \Deleted flag set from the currently selected mailbox. Yes
FETCH/UID FETCH Retrieves data associated with a message in the mailbox. Yes
UID Unique identifier. Yes
LIST Returns a subset of names from the complete set of all names available to the client. Yes
LOGIN Identifies the client to the server and carries the plaintext password authenticating this user. Yes
LOGOUT Informs the server that the client is done with the connection. No
LSUB Returns a subset of names from the set of names that the user has declared as being “active” or “subscribed”. Yes
NOOP Does nothing. It always succeeds. Yes
RENAME Changes the name of a mailbox. No
SEARCH Searches the mailbox for messages that match the given searching criteria. Yes
SELECT Selects a mailbox so that messages in the mailbox can be accessed. Yes
STORE Alters data associated with a message in the mailbox. Yes
SUBSCRIBE Adds the specified mailbox name to the server’s set of “active” or “subscribed” mailboxes as returned by the LSUB command. No
UNSUBSCRIBE Removes the specified mailbox name from the server’s set of “active” or “subscribed” mailboxes as returned by the LSUB command. No