diff --git a/plugins/calendar/drivers/calendar_driver.php b/plugins/calendar/drivers/calendar_driver.php
index b0687728..d4e732ce 100644
--- a/plugins/calendar/drivers/calendar_driver.php
+++ b/plugins/calendar/drivers/calendar_driver.php
@@ -46,7 +46,7 @@
  *    ),
  * 'recurrence_id' => 'ID of the recurrence group',   // usually the ID of the starting event
  *    'categories' => 'Event category',
- *     'free_busy' => 'free|busy|outofoffice',  // Show time as
+ *     'free_busy' => 'free|busy|outofoffice|tentative',  // Show time as
  *      'priority' => 1|0|2,   // Event priority (0=low, 1=normal, 2=high)
  *   'sensitivity' => 0|1|2,   // Event sensitivity (0=public, 1=private, 2=confidential)
  *        'alarms' => '-15M:DISPLAY',  // Reminder settings inspired by valarm definition (e.g. display alert 15 minutes before event)
diff --git a/plugins/calendar/drivers/database/database_driver.php b/plugins/calendar/drivers/database/database_driver.php
index f79f5c63..319f859e 100644
--- a/plugins/calendar/drivers/database/database_driver.php
+++ b/plugins/calendar/drivers/database/database_driver.php
@@ -35,7 +35,7 @@ class database_driver extends calendar_driver
   private $cal;
   private $calendars = array();
   private $calendar_ids = '';
-  private $free_busy_map = array('free' => 0, 'busy' => 1, 'out-of-office' => 2, 'outofoffice' => 2);
+  private $free_busy_map = array('free' => 0, 'busy' => 1, 'out-of-office' => 2, 'outofoffice' => 2, 'tentative' => 3);
   
   private $db_events = 'events';
   private $db_calendars = 'calendars';