In addition to a slight performance boost, there are a number of new features and bug fixes which you will probably notice after a little while. There's a fix for the "from" column for example (!) and the annoying habit of missing off the .sig when replying to email.

For those of you with the Office groupware option, there's now a fully implemented Calendar / Tasks system with sharing facilities. (and of course there's the shared folder facility!)

Here's a more technical rundown;

New Features for 5.0 (Release Notes from Zimbra)

Following is a list of major enhancements for ZCS 5.0.2.

• Task Lists. Off by default when you upgrade. A new Tasks tab is added to the application tabs. The tasks list feature includes the ability to create multiple task lists, create tasks, mange a task, including setting the priority and tracking the progress
• Documents. On by default when you upgrade. Documents is a document sharing and collaboration application that gives you a central place on the Zimbra Web Client to develop, organize, and share information
• Briefcase. Off by default when you upgrade. Briefcase lets you save files on the Zimbra Web Client so that you can access them whenever you log on to the ZWC
• Delegated Mailbox. Users can share any of their email folders, including the Inbox and sub-folders
• Users can be notified when their mailbox is almost full (quota feature)
• Calendar entries can be marked private or public
• Search for an appointment up to 180 days in the future
• Photos and images can be uploaded and synced to the address book contacts list
• Message priority can be set
• Instant notification of email messages can be enabled
• Major changes to the administration console include:
• Layout of the administration console has been improved. You can open more than one function at a time. Tabs are opened above the Content pane
• Search queries can be saved
• Search for all administrators and domain administrators on ZCS
• Last login time is displayed from the administration console Accounts content pane
• Default time zone set in the COS/Admin can now be changed by users. This timezone is used for Zimbra Mobile and the standard Zimbra Web client
• Monitoring, Server Statistics for individual servers now includes a Sessions tab that displays information about active web client, administrator and IMAP sessions
• Certificates can be managed and installed from the administration console
• The Jetty Web server is now used as the server container that the Zimbra software runs within. Reference to this servlet is called mailboxd
• Domain name can be changed from the zmprov CLI

• Ngnix is used to support more scalable POP/IMAP proxy

• Domain’s status can be set, including status of Suspended
• Account level logging can be configured
• ZCS HTTP mode now includes Redirect. Redirect mode redirects any users connecting via HTTP to a HTTPS connection
• If more than one language locale has been installed on ZCS, users have the option to select the locale that is different from the browser language settings from the Preferences, General tab
• Major import and migration feature enhancements:
• Tasks can be imported/migrated
• The types of items (appointments, email, contacts, and tasks) to import can be selected
• Photos associated with contacts can be imported/migrated
• Appointments and tasks private status is retained
  

Enhancements for 5.0.X

• Spell check is now available in the standard Zimbra Web Client. (Bug 16819)
• LDAP configuration can now be enabled separately for GAL search and for GAL Sync. When ZCS is installed, the default is GAL search and GAL Sync have the same configuration. You can change this from the administration console in the GAL configuration wizard and new domain wizard. (Bug 21247)
• Change to spam fiiltering. In ZCS 5.0.1 and earlier, user filters were run before the spam filter check was run. This meant that if the user filtered mail into a folder, spam would not be identified and sent to the Junk folder. Beginning with 5.0.2, spam check is completed first and messages identified as spam are moved to the Junk folder. With this change, users cannot write a filter to move false positive spam out of the Junk folder. You can create a spam white list for individual accounts that allows an account to identify email addresses that should not be marked as spam. To do this, type
  
  zmprov ma <account@example.com> +amavisWhiteListSender <name@example.com> +amavisWhiteListSender <name2@example2.com>
  
  Note: If you prefer ZCS 5.0.2 or later to use the spam filter function as it works for 5.0.1 and earlier, you can set the zimbraSpamApplyUserFilters option to True. This can be done by COS or for individual accounts. (Bug 23886)
  

Miscellaneous Important Notices

• With the introduction of Ngnix for proxy, memcached is shipped as the caching layer to cache LDAP lookups. Memcache does not have authentication and security features so the servers should have a firewall set up appropriately. The default port is 11211 and is controlled by zimbraMemcacheBindPort conf setting in zimbraserver. (Bug 22869)
  

• For SMTP auth to work in round-robin fashion for authentication, the administration port 7071 must be visible from each MTA servers (Bug 6218).
• Message purge is no longer scheduled through the crontab. The server manages the message purge schedule. The default is message purge is not enabled. If you previously had message purge scheduled in the crontab, you will want to change the zimbraMailPurgeSleepInterval attribute from 0. Set it to the duration of time that the server should “rest” between purging mailboxes. The command to change this attribute is zmprov ModifyServer <server-name> zimbraMailPurgeSleepInterval <X>. X is the duration of time between mailbox purges.

Beta-quality features included with ZCS 5.0

These features included with are considered beta quality and have known issues.

• Instant Messaging - IM lets users exchange messages in real time with other users in ZCS. Users can create buddy lists. IM interactions are saved to the Chat folder.
  
  Note: Update about Instant Messaging feature - In order to ensure the scalability of our server software and provide a quality experience to our customers, we have removed IM interoperability with AOL and MSN that was present in previous 5.0.0 beta releases. This functionality may be restored in a future release.
• SafariTM browser support is in beta and there are several known issues.
• Zimbra Toaster is a stand-alone application that notifies users when new email is delivered to their ZCS mailbox. The install format is an .msi file.
  

You can find more information on the Zimbra website at http://zimbra.com