• Added: Partly RFC3744 ACL support.
• Added: Calendar-delegation (caldav-proxy) support.
• BC break: In order to fix Issue 99, a new argument had to be added to
  Sabre_DAV_Locks_Backend_*::getLocks classes. Consult the classes for details.
• Deprecated: Sabre_DAV_Locks_Backend_FS is now deprecated and will be removed
  in a later version. Use PDO or the new File class instead.
• Deprecated: The Sabre_CalDAV_ICalendarUtil class is now marked deprecated, and
  will be removed in a future version. Please use Sabre_VObject instead.
• Removed: All principal-related functionality has been removed from the
  Sabre_DAV_Auth_Plugin, and moved to the Sabre_DAVACL_Plugin.
• Added: VObject library, for easy vcard/icalendar parsing using a natural
  interface.
• Added: Ability to automatically generate full .ics feeds off calendars. To
  use: Add the Sabre_CalDAV_ICSExportPlugin, and add ?export to your calendar
  url.
• Added: Plugins can now specify a pluginname, for easy access using
  Sabre_DAV_Server::getPlugin().
• Added: beforeGetProperties event.
• Added: updateProperties event.
• Added: Principal listings and calendar-access can now be done privately,
  disallowing users from accessing or modifying other users' data.
• Added: You can now pass arrays to the Sabre_DAV_Server constructor. If it's an
  array with node-objects, a Root collection will automatically be created, and
  the nodes are used as top-level children.
• Added: The principal base uri is now customizable. It used to be hardcoded to
  'principals/[user]'.
• Added: getSupportedReportSet method in ServerPlugin class. This allows you to
  easily specify which reports you're implementing.
• Added: A '..' link to the HTML browser.
• Fixed: Issue 99: Locks on child elements were ignored when their parent nodes
  were deleted.
• Fixed: Issue 90: lockdiscovery property and LOCK response now include a
  {DAV}lockroot element.
• Fixed: Issue 96: support for 'default' collation in CalDAV text-match filters.
• Fixed: Issue 102: Ensuring that copy and move with identical source and
  destination uri's fails.
• Fixed: Issue 105: Supporting MKCALENDAR with no body.
• Fixed: Issue 109: Small fixes in Sabre_HTTP_Util.
• Fixed: Issue 111: Properly catching the ownername in a lock (if it's a string)
• Fixed: Sabre_DAV_ObjectTree::nodeExist always returned false for the root
  node.
• Added: Global way to easily supply new resourcetypes for certain node classes.
• Fixed: Issue 59: Allowing the user to override the authentication realm in
  Sabre_CalDAV_Server.
• Update: Issue 97: Looser time-range checking if there's a recurrence rule in
  an event. This fixes 'missing recurring events'.