# Cyrus IMAP 3.3.0 Tag Notes

Unavailable for download as this is a development branch only.

Access is via git.

Warning

This should be considered for testing purposes and bleeding-edge features only. We will try to tag these snapshots at coherent development points, but there will generally be large breaking changes occurring between releases in this series.

## Major changes since the 3.2 series

- DAV improvements

- Improved performance for users with large folders

- LITERAL- maximum size is now honoured (RFC 7888)

- Support for the ESORT (but not CONTEXT) extension from RFC 5267

- Experimental JMAP for Sieve Scripts support (requires jmap_nonstandard_extensions: yes in imapd.conf(5)).

- Experimental Handling Message Disposition Notification with JMAP support (requires jmap_nonstandard_extensions: yes in imapd.conf(5)).

- Experimental JMAP Backup extension (requires jmap_nonstandard_extensions: yes in imapd.conf(5)).

- Experimental JMAP Notes extension (requires jmap_nonstandard_extensions: yes in imapd.conf(5)).

- Experimental JMAP Blob extension (requires jmap_nonstandard_extensions: yes in imapd.conf(5)).

- Experimental JMAP Mail extension (requires jmap_nonstandard_extensions: yes in imapd.conf(5)).

- New cyrus.index format v17 adds changes_epoch field, needed by JMAP Backups extension

- New reverseuniqueids imapd.conf(5) option (default on), which improves performance for users with large mailboxes

- Further improvements to the reverseacls imapd.conf(5) performance option

- Improvements to replication reliability and performance

- Experimental vnd.cyrus.log, vnd.cyrus.jmapquery, and vnd.cyrus.snooze Sieve extensions

- Improvements to conversations

- New mailbox_maxmessages_addressbook, mailbox_maxmessages_calendar, and mailbox_maxmessages_email imapd.conf(5) options for providing server-wide limits on the amount of objects in any one mailbox, independently of quotas. These default to 0 (unlimited) for backward compatibility, but are highly recommended for protecting your server from misbehaving clients.

- New IMAP create/delete behaviour based on draft-ietf-extra-imap4rev2: mailboxes containing child mailboxes can no longer be deleted; and when creating mailboxes, ancestors will be created as needed.

- CRC32 optimisations

## Updates to default configuration

The cyr_info(8) conf, conf-all and conf-default subcommands accept an -s <version> argument to highlight imapd.conf(5) options that are new or whose behaviour has changed since the specified version. We recommend using this when evaluating a new Cyrus version to check which configuration options you will need to examine and maybe set or change during the process.

- None so far

## Security fixes

- None so far

## Significant bugfixes

- Fixed: Sieve Editheader Extension (RFC 5293) now works correctly with respect to section 7, Interaction with Other Sieve Extensions.