Cyrus IMAP is an email, contacts and calendar server

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master: stable(3.6):


This is the Cyrus IMAP Server, developer version 3.9. This version is under active development, and is not considered "stable".

The current stable series is 3.8.

Versions 3.0 to 3.6 still receive security updates, and some non-security bug fixes.

What is Cyrus

Cyrus is an IMAP server, where IMAP (Internet Message Access Protocol) is a protocol for accessing mail.

The Cyrus IMAP server differs from other IMAP server implementations in that it is generally intended to be run on "sealed" servers, where normal users are not permitted to log in. The mailbox database is stored in parts of the filesystem that are private to the Cyrus IMAP system. All user access to content is through JMAP, IMAP, NNTP, POP3, CalDAV, CardDAV, and WebDAV protocols.

The private mailbox database design gives the server large advantages in efficiency, scalability, and administrability. 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.

Cyrus goals

To be the best open source secure, scalable mail server, providing breadth and depth of functionality across email, contacts, calendar and related messaging services!

How to get Cyrus

Cyrus comes in three flavours:

  1. Our release source tarballs from
    • Recommended for most users.
    • These are packaged by the Cyrus team.
    • The docs are pre-built for you in doc/html.
    • They're definitively tagged to a particular release version with up to date release notes.
  2. Raw source from
    • Use this if you need a version of Cyrus that contains an unreleased patch/fix/feature.
    • These bundles require a lot more dependencies to build than a packaged tarball.
  3. Operating System distribution packages.
    • Cyrus IMAP packages are shipped with every major distribution, including but not limited to Fedora, Red Hat Enterprise Linux, CentOS, Scientific Linux, Debian, Ubuntu, openSUSE, Gentoo, Mageia and ClearOS.
    • Please be aware that we don't maintain these packages and as such, some distributions are out of date.
    • If you run into problems with a packed distribution, please contact the source of the distribution.

How to install Cyrus from packaged releases

Please be sure to read the documentation. The latest version is online at, but the version current for this distribution can be found in the doc/ subdirectory.

For Cyrus tarball releases, the basic installation instructions are:

$ ./configure
$ make
$ sudo make install

For more detailed instructions see: doc/html/imap/

How to install Cyrus from git source

The Cyrus source is available at:

For version 3.0 or later, please first build Cyrus main dependencies from source (see next section).

The latest development code is on the branch called 'master', and the latest code destined for the stable release is on the branch 'cyrus-imapd-$major.$minor'. So the current stable release is called cyrus-imapd-3.8

Unlike releases, the git repository doesn't have a pre-built ./configure script. You need to generate it with autoreconf:

$ autoreconf -i
$ ./configure
$ make
$ sudo make install

GNU Make is required. If you're not on Linux, it might be called 'gmake'.

If you need to build a local copy of the docs current to the version of the code, these need to be built: see doc/

Read through doc/html/imap/developer.html for more detailed instructions on building and contributing. The latest version is online at

How to install Cyrus libraries from git source

For version 3.0 or later, it is recommended to also build the main dependencies from source.

If you intend to use Xapian for search, we strongly recommend to use the custom Xapian fork in cyruslibs. However, if this is not an option in your environment, please fetch the latest stable upstream Xapian release. Cyrus will omit custom features such as word boundary analysis for Chinese, Japanese and Korean.

The Cyrus dependencies source is available at:

To build and install the libraries, run

$ ./

By default, all dependencies are installed in /usr/local/cyruslibs. Before compiling Cyrus from git source, make sure to update your environment variables, accordingly. For example:

$ export CYRUSLIBS=/usr/local/cyruslibs
$ export LDFLAGS="-Wl,-rpath,$CYRUSLIBS/lib -Wl,-rpath,$CYRUSLIBS/lib/x86_64-linux-gnu"

For Xapian, either make sure to add $CYRUSLIBS/bin to your PATH, or call Cyrus ./configure script as follows:

$ ./configure XAPIAN_CONFIG="$CYRUSLIBS/bin/xapian-config-1.5" [...]

(If you do not use Xapian from cyruslibs, you'll need to locate the xapian-config binary and substitute XAPIAN_CONFIG accordingly).

Then continue to install Cyrus.

Are you upgrading?

Read doc/html/imap/download/upgrade.html

Think you've found a bug or have a new feature?

Fantastic! We'd love to hear about it, especially if you have a patch to contribute.

The best way to make contributions to the project is to fork it on github, make your changes on your fork, and then send a pull request.

Check for any outstanding bugs.

Our guide at has all the information about how to contact us and how best to get your change accepted.

Licensing Information

See the COPYING file in this distribution.

Contact us

Whether you have a success story to share, or a bug to file, or a request for help or a feature to add or some documentation to contribute or you'd just like to say hi, we want to hear from you! See for various ways you can get hold of us.

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