| Feature | Status | 3.x | 2.3.x | Since | First released |
|---|---|---|---|---|---|
| SMTP | Stable | yes | yes | 1.0 | 0.95 |
| POP3 | Stable | yes | yes | 1.1 | 1.0 |
| IMAP | Stable | yes | no | 3.0 | 3.0 |
| JMAP | Experimental | yes | no | 3.0 | 3.0 |
| LMTP | Stable | yes | no | ||
| ManageSieve | Experimental | yes | no | 3.0.0 | 3.0.0 |
| NNTP | Dropped (3.x) | no | yes | 1.2 | 1.2 |
| TLS POP3/SMTP/IMAP | Stable | yes | yes | 1.2 | 1.2 |
| Mailing List | Dropped (3.x) | no | yes | ||
| FetchMail | Experimental | yes | yes | 2.2 | 2.2 |
| Mailet Container | Stable | yes | yes | 2.3 | 0.95 |
| Remote Manager | Stable | yes | yes | 1.0 | 1.0 |
| Management via JMX | Experimental | yes | yes | ||
| TLS Remote Manager | Dropped (3.x) | yes | yes | 1.2 | 1.2 |
| JPA Mailbox | Legacy | yes | no | ||
| Cassandra Mailbox | Stable | yes | no | 3.0.0 | 3.0.0 |
| Lucene search | Legacy | yes | no | ||
| OpenSearch search | Stable | yes | no | 3.0.0 | 3.0.0 |
| Simple search | Stable but not advised | yes | no | 3.0.0 | 3.0.0 |
| File Mail Store | Stable | yes | yes | 1.2 | 1.0 |
| JPA Database Mail Store | Experimental | yes | no | ||
| JPA Users | Stable | yes | no | 1.2.1 | 1.2.1 |
| Cassandra Users | Stable | yes | no | 3.0.0 | 3.0.0 |
| LDAP Users | Stable | yes | yes | 1.2 | 1.2 |
| ActiveMQ Queue | Stable | yes | no | ||
| RabbitMQ Queue | Stable | yes | no | ||
| Integration with SpamAssassin | Stable | yes | partial | ||
| SIEVE scripts | Experimental | yes | no | 3.0.0 | 3.0.0 |
| Monitoring via JMX | Experimental | yes | yes | ||
| IP V6 | Experimental | partial | no | ||
| Java 1.21 | Requirement | yes | no |