diff --git a/plugins/calendar/drivers/kolab/kolab_calendar.php b/plugins/calendar/drivers/kolab/kolab_calendar.php
index 3703f85a..e20133e1 100644
--- a/plugins/calendar/drivers/kolab/kolab_calendar.php
+++ b/plugins/calendar/drivers/kolab/kolab_calendar.php
@@ -60,7 +60,7 @@ class kolab_calendar
 
     // Set readonly and alarms flags according to folder permissions
     if ($this->ready) {
-      if ($this->get_owner() == $_SESSION['username']) {
+      if ($this->storage->get_namespace() == 'personal') {
         $this->readonly = false;
         $this->alarms = true;
       }
diff --git a/plugins/tasklist/drivers/kolab/tasklist_kolab_driver.php b/plugins/tasklist/drivers/kolab/tasklist_kolab_driver.php
index 3aef4dc7..0f9d35d1 100644
--- a/plugins/tasklist/drivers/kolab/tasklist_kolab_driver.php
+++ b/plugins/tasklist/drivers/kolab/tasklist_kolab_driver.php
@@ -94,7 +94,7 @@ class tasklist_kolab_driver extends tasklist_driver
 
             $name = kolab_storage::folder_displayname(kolab_storage::object_name($utf7name), $listnames);
 
-            if ($folder->get_owner() == $_SESSION['username']) {
+            if ($folder->get_namespace() == 'personal') {
                 $readonly = false;
                 $alarms = true;
             }