diff --git a/plugins/calendar/calendar.php b/plugins/calendar/calendar.php
index d6010afa..f618f5b3 100644
--- a/plugins/calendar/calendar.php
+++ b/plugins/calendar/calendar.php
@@ -109,7 +109,7 @@ class calendar extends rcube_plugin
       $this->register_action('freebusy-status', array($this, 'freebusy_status'));
       $this->register_action('freebusy-times', array($this, 'freebusy_times'));
       $this->register_action('randomdata', array($this, 'generate_randomdata'));
-	  $this->register_action('print',array($this,'print_view'));
+      $this->register_action('print',array($this,'print_view'));
     } 
     else if ($this->rc->task == 'settings') {
       // add hooks for Calendar settings
diff --git a/plugins/calendar/calendar_ui.js b/plugins/calendar/calendar_ui.js
index 4889b2e4..7576e8d8 100644
--- a/plugins/calendar/calendar_ui.js
+++ b/plugins/calendar/calendar_ui.js
@@ -1457,6 +1457,7 @@ window.rcmail && rcmail.addEventListener('init', function(evt) {
   rcmail.addEventListener('plugin.reload_calendar', function(p){ $('#calendar').fullCalendar('refetchEvents', cal.calendars[p.source]); });
   rcmail.addEventListener('plugin.destroy_source', function(p){ cal.calendar_destroy_source(p.id); });
   rcmail.addEventListener('plugin.unlock_saving', function(p){ rcmail.set_busy(false, null, cal.saving_lock); });
+  rcmail.addEventListener('plugin.ping_url', function(p){ p.event = null; new Image().src = rcmail.url(p.action, p); });
 
   // let's go
   var cal = new rcube_calendar_ui(rcmail.env.calendar_settings);
diff --git a/plugins/calendar/drivers/kolab/kolab_calendar.php b/plugins/calendar/drivers/kolab/kolab_calendar.php
index edc12b12..d6cd3b5b 100644
--- a/plugins/calendar/drivers/kolab/kolab_calendar.php
+++ b/plugins/calendar/drivers/kolab/kolab_calendar.php
@@ -150,6 +150,14 @@ class kolab_calendar
   }
 
 
+  /**
+   * Return the corresponding Kolab_Folder instance
+   */
+  public function get_folder()
+  {
+    return $this->storage->_folder;
+  }
+
   /**
    * Getter for the attachment body
    */
diff --git a/plugins/calendar/drivers/kolab/kolab_driver.php b/plugins/calendar/drivers/kolab/kolab_driver.php
index 1bc26d78..2b78b06d 100644
--- a/plugins/calendar/drivers/kolab/kolab_driver.php
+++ b/plugins/calendar/drivers/kolab/kolab_driver.php
@@ -41,6 +41,8 @@ class kolab_driver extends calendar_driver
     $this->cal = $cal;
     $this->rc = $cal->rc;
     $this->_read_calendars();
+    
+    $this->cal->register_action('push-freebusy', array($this, 'push_freebusy'));
   }
 
 
@@ -239,7 +241,13 @@ class kolab_driver extends calendar_driver
         }
       }
 
-      return $storage->insert_event($event);
+      $GLOBALS['conf']['kolab']['no_triggering'] = true;
+      $success = $storage->insert_event($event);
+      
+      if ($success)
+        $this->rc->output->command('plugin.ping_url', array('action' => 'push-freebusy', 'source' => $storage->id));
+      
+      return $success;
     }
 
     return false;
@@ -299,6 +307,8 @@ class kolab_driver extends calendar_driver
       $savemode = 'all';
       $master = $event;
       
+      $GLOBALS['conf']['kolab']['no_triggering'] = true;
+      
       // read master if deleting a recurring event
       if ($event['recurrence'] || $event['recurrence_id']) {
         $master = $event['recurrence_id'] ? $storage->get_event($event['recurrence_id']) : $event;
@@ -327,6 +337,9 @@ class kolab_driver extends calendar_driver
       }
     }
 
+    if ($success)
+      $this->rc->output->command('plugin.ping_url', array('action' => 'push-freebusy', 'source' => $storage->id));
+
     return $success;
   }
 
@@ -384,6 +397,8 @@ class kolab_driver extends calendar_driver
     if ($old['recurrence']['EXDATE'])
       $event['recurrence']['EXDATE'] = $old['recurrence']['EXDATE'];
 
+    $GLOBALS['conf']['kolab']['no_triggering'] = true;
+    
     switch ($savemode) {
       case 'new':
         // save submitted data as new (non-recurring) event
@@ -459,6 +474,9 @@ class kolab_driver extends calendar_driver
         break;
     }
     
+    if ($success)
+      $this->rc->output->command('plugin.ping_url', array('action' => 'push-freebusy', 'source' => $storage->id));
+    
     return $success;
   }
 
@@ -668,9 +686,31 @@ class kolab_driver extends calendar_driver
     if (empty($email)/* || $end < time()*/)
       return false;
     
-    // load and parse free-busy information using Horde classes
-    $fburl = rcube_kolab::get_freebusy_url($email);
-    if ($fbdata = file_get_contents($fburl)) {
+    // ask kolab server first
+    $fbdata = @file_get_contents(rcube_kolab::get_freebusy_url($email));
+      
+    // get free-busy url from contacts
+    if (!$fbdata) {
+      $fburl = null;
+      foreach ((array)$this->rc->config->get('autocomplete_addressbooks', 'sql') as $book) {
+        $abook = $this->rc->get_address_book($book);
+        
+        if ($result = $abook->search(array('email'), $email, true, true, true/*, 'freebusyurl'*/)) {
+          while ($contact = $result->iterate()) {
+            if ($fburl = $contact['freebusyurl']) {
+              $fbdata = @file_get_contents($fburl);
+              break;
+            }
+          }
+        }
+        
+        if ($fbdata)
+          break;
+      }
+    }
+    
+    // parse free-busy information using Horde classes
+    if ($fbdata) {
       $fbcal = new Horde_iCalendar;
       $fbcal->parsevCalendar($fbdata);
       if ($fb = $fbcal->findComponent('vfreebusy')) {
@@ -687,5 +727,33 @@ class kolab_driver extends calendar_driver
     
     return false;
   }
+  
+  /**
+   * Handler to push folder triggers when sent from client.
+   * Used to push free-busy changes asynchronously after updating an event
+   */
+  public function push_freebusy()
+  {
+    // make shure triggering completes
+    set_time_limit(0);
+    ignore_user_abort(true);
+
+    $cal = get_input_value('source', RCUBE_INPUT_GPC);
+    if (!($storage = $this->calendars[$cal]))
+      return false;
+    
+    // trigger updates on folder
+    $folder = $storage->get_folder();
+    $trigger = $folder->trigger();
+    if (is_a($trigger, 'PEAR_Error')) {
+      raise_error(array(
+        'code' => 900, 'type' => 'php',
+        'file' => __FILE__, 'line' => __LINE__,
+        'message' => "Failed triggering folder. Error was " . $trigger->getMessage()),
+        true, false);
+    }
+    
+    exit;
+  }
 
 }