Its features include encrypted access using SSL, anti-virus and anti-spam protection, native over-the-air handheld synchronization, comfortable webmail interface, connector for Microsoft Outlook and groupware features.
Administration is by a separate console application which can be run remotely. There is also a very limited web based administration facility.
Messages are stored on the server as individual files with separate index files. This contrasts with systems such as Microsoft Exchange which use a database to store messages.
CalDAV support was added in version 6.5[1] for software, such as Mozilla Sunbird, and newer versions of Apple iCal and Apple's Address Book application.
Support for older versions of Apple iCal and Address Book prior to Mac OS X 10.5 is provide via the Kerio iSync connector software.
groupware features (shared calendar, contacts, tasks, etc.), MS Outlook integration using Kerio Outlook Connector, new re-vamped WebMail, new SpamAssassin engine, learning Bayesian filter, new backup and recovery, migration tool from MS Exchange, SMTP routing for multi-location deployments, new non-commercial blacklists
WebMail mini, support for Mac OS X v10.4 (Tiger), Kerio Synchronization Plug-in for Outlook, contact synchronization with Apple Address Book, support for Apple iCal, improved and enhanced anti-spam filtering, Sender Policy Framework, HTML editor in new mail composer in WebMail, free/busy dialog in WebMail, Web Administration interface for domain administration
Two-level spam rating, Distribution lists, Sticky Notes, antivirus plug-in for Clam AntiVirus, universal binaries on Mac OS X, visual marker to WebMail drag'n'drop
New Web Administration, better iPhone support, ActiveSync 12, tool for massive Outlook Connector deployment, enhanced iCal integration, ability to auto delete old mails, resource scheduling, support for CentOS and Firefox 3.