IMAP Server Specifications
The different capabilities of the different imap servers.
| RFC | Name | Capability name | Courier | Cyrus | DBMail | Dovecot | UW-IMAP |
| 2087 | IMAP4 QUOTA extension | QUOTA | yes | yes | yes | v1.0 | no |
| 2088 | IMAP4 non-synchronizing literals | LITERAL+ | no | v1.5 | no | v1.0 | yes |
| 2177 | IMAP4 IDLE command | IDLE | yes | v2.0 | yes | v1.0 | yes |
| 2193 | IMAP4 Mailbox Referrals | MAILBOX-REFERRALS | no | v2.1 | no | no | yes |
| 2221 | IMAP4 Login Referrals | LOGIN-REFERRALS | no | no | no | v1.0 | yes |
| 2342 | IMAP4 Namespace | NAMESPACE | yes | v1.6 | yes | v1.0 | yes |
| 2971 | IMAP4 ID extension | ID | no | v1.6 | no | v1.2 | no |
| 3348 | IMAP4 Child Mailbox Extension | CHILDREN | yes | v2.1 | yes | v1.0 | yes |
| 3502 | IMAP4 MULTIAPPEND Extension | MULTIAPPEND | no | v2.0 | no | v1.0 | yes |
| 3516 | IMAP4 Binary Content Extension | BINARY | no | v2.2 | no | no | yes |
| 3691 | http://www.ietf.org/rfc/rfc3691.txt IMAP4 UNSELECT command] | UNSELECT | no | v1.6 | yes | v1.0 | yes |
| 4314 | IMAP4 Access Control List (ACL) Extension | ACL | yes | yes | yes | v1.2 | no |
| 4314 | IMAP4 Access Control List (ACL) Extension | RIGHTS=* | no | v2.3 | no | v1.2 | no |
| 4315 | IMAP UIDPLUS extension | UIDPLUS | yes | v1.6 | no | v1.1 | yes |
| 4467 | IMAP - URLAUTH Extension | URLAUTH | no | v2.4 | no | no | no |
| 4469 | IMAP CATENATE Extension | CATENATE | no | v2.3 | no | no | no |
| 4551 | IMAP Extension for Conditional STORE Operation or Quick Flag Changes Resynchronization | CONDSTORE | no | v2.3 | no | v1.2 | no |
| 4731 | IMAP4 Extension to SEARCH Command for Controlling What Kind of Information Is Returned | ESEARCH | no | v2.4 | no | v1.2 | yes |
| 4959 | IMAP Extension for Simple Authentication and Security Layer (SASL) Initial Client Response | SASL-IR | no | v2.2 | no | v1.1 | yes |
| 4978 | The IMAP COMPRESS Extension | COMPRESS=DEFLATE | no | v2.4 | no | v2.0 | no |
| 5032 | WITHIN Search Extension to the IMAP Protocol | WITHIN | no | v2.4 | no | v1.2+ | yes |
| 5162 | IMAP4 Extensions for Quick Mailbox Resynchronization | QRESYNC | no | v2.4 | no | v1.2 | no |
| 5182 | IMAP Extension for Referencing the Last SEARCH Result | SEARCHRES | no | no | no | v1.2 | no |
| 5255 | IMAP Internationalization | I18NLEVEL=1 | no | no | no | v1.1 | yes |
| 5255 | IMAP Internationalization | I18NLEVEL=2 | no | no | no | no | no |
| 5256 | IMAP SORT and THREAD Extensions | SORT | yes | v2.0 | yes | v1.0 | yes |
| 5256 | IMAP SORT and THREAD Extensions | THREAD=ORDEREDSUBJECT | yes | v2.0 | yes | no | yes |
| 5256 | IMAP SORT and THREAD Extensions | THREAD=REFERENCES | yes | v2.0 | no | v1.0 | yes |
| 5257 | IMAP - ANNOTATE Extension | ANNOTATE-EXPERIMENT-1 | no | no | no | no | no |
| 5258 | IMAP4 - LIST Command Extensions | LIST-EXTENDED | no | v2.4 | no | v1.1 | no |
| 5259 | IMAP - CONVERT Extension | CONVERT | no | no | no | no | no |
| 5267 | Contexts for IMAP4 | ESORT | no | no | no | v1.2 | no |
| 5267 | Contexts for IMAP4 | CONTEXT=SEARCH | no | no | no | v1.2 | no |
| 5267 | Contexts for IMAP4 | CONTEXT=SORT | no | no | no | no | no |
| 5464 | The IMAP METADATA Extension | METADATA | no | no | no | no | no |
| 5465 | The IMAP NOTIFY Extension | NOTIFY | no | no | no | no | no |
| 5466 | IMAP4 Extension for Named Searches (Filters) | FILTERS | no | no | no | no | no |
| 5524 | Extended URLFETCH for Binary and Converted Parts | URLAUTH=BINARY | no | v2.4 | no | no | no |
| 5530 | IMAP Response Codes | - | no | no | no | v1.2 | no |
| 5819 | IMAP4 Extension for Returning STATUS Information in Extended LIST | LIST-STATUS | no | no | no | v1.2 | no |