Projects / Cyrus IMAP Server

Cyrus IMAP Server

The Cyrus IMAP server is generally intended to be run on sealed systems, where normal users are not permitted to log in. The mailbox database is stored in parts of the filesystem that are private to Cyrus. All user access to mail is through the IMAP, POP3, or KPOP protocols. The private mailbox database design gives the server large advantages in efficiency, scalability, and administratability. Multiple concurrent read/write connections to the same mailbox are permitted. The server supports access control lists on mailboxes and storage quotas on mailbox hierarchies, multiple SASL mechanisms, and the Sieve mail filtering language.


Recent releases

  •  12 Mar 2012 15:10

    Release Notes: This release resolves numerous bugs, including many related to folder management and naming, and improves compatibility with iOS clients.

    •  02 May 2011 10:18

      Release Notes: Unlimited quotas are now supported by proxy servers. Compatibility with mailbox LIST operations was improved. Security vulnerabilities regarding STARTTLS operations were corrected. Many other bug fixes and performance improvements were made.

      •  20 Oct 2010 11:28

        Release Notes: Full support was added for the CONDSTORE and QRESYNC extensions. Support was added for IMAP extensions that are part of the LEMONADE support, including LIST-EXTENDED, COMPRESS, ESEARCH, WITHIN, ENABLE, QRESYNC, and partial support for URLAUTH=BINARY. Metadata and mailbox index databases have been overhauled for greatly improved scalability. Synchronization (clustering) protocols have been rewritten for greater reliability and improved extensibility.

        •  09 Sep 2009 14:44

          Release Notes: This release corrects a potential buffer overflow in Sieve, has improvements in murder and partition management including introduction of the cyr_df utility, and has bugfixes for skiplist on 64-bit platforms, squatter indexing, and other issues.

          •  26 Jun 2009 18:44

            Release Notes: Stability and performance improvements as well as significant replication related bugfixes. Quota calculation works in delayed expunge mode.

            Recent comments

            29 Jul 2002 04:56 simix

            2.1.x RPMs for RedHat 7.x
            I have created 2.1.x RPMs for RH 7.x.
            For now, you can find them here:

            15 Jun 2002 16:24 winnetou

            Re: RPM packages available - site moved
            * Wed Mar 13 2002

            - Move page to new hosting site.


            it is now at: (

            20 Jul 2001 18:16 ramirom

            RPM packages available
            The URL (where full description and release notes can be found) is:


            The packages can be compiled and installed in Red Hat Linux 6.2, 7 and 7.1.


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