diff --git a/plugins/libkolab/README b/plugins/libkolab/README
index a16250f1..a60d5487 100644
--- a/plugins/libkolab/README
+++ b/plugins/libkolab/README
@@ -12,5 +12,9 @@ REQUIREMENTS
 * libkolabxml PHP bindings
   - kolabformat.so loaded into PHP
   - kolabformat.php placed somewhere in the include_path
-* Horde Kolab_Format package and all of its dependencies
+* PEAR: HTTP/Request2
+* PEAR: Net/URL2
 
+* Optional for old format support:
+  Horde Kolab_Format package and all of its dependencies
+  which are at least Horde_(Browser,DOM,NLS,String,Utils)
diff --git a/plugins/libkolab/lib/kolab_storage_folder.php b/plugins/libkolab/lib/kolab_storage_folder.php
index 6c4b4010..1fc84cf5 100644
--- a/plugins/libkolab/lib/kolab_storage_folder.php
+++ b/plugins/libkolab/lib/kolab_storage_folder.php
@@ -712,7 +712,7 @@ class kolab_storage_folder
             return true;
         }
 
-        if ($result && is_a($result, 'PEAR_Error')) {
+        if ($result && is_object($result) && is_a($result, 'PEAR_Error')) {
             return PEAR::raiseError(sprintf("Failed triggering folder %s. Error was: %s",
                                             $this->name, $result->getMessage()));
         }
@@ -730,18 +730,23 @@ class kolab_storage_folder
      */
     private function trigger_url($url, $auth_user = null, $auth_passwd = null)
     {
-        require_once('HTTP/Request.php');
+        require_once('HTTP/Request2.php');
 
-        $request = new HTTP_Request($url);
+        try {
+            $request = new HTTP_Request2($url);
 
-        // set authentication credentials
-        if ($auth_user && $auth_passwd)
-            $request->setBasicAuth($auth_user, $auth_passwd);
+            // set authentication credentials
+            if ($auth_user && $auth_passwd)
+                $request->setAuth($auth_user, $auth_passwd);
 
-        $result = $request->sendRequest(true);
-        // rcube::write_log('trigger', $request->getResponseBody());
+            $result = $request->send();
+            // rcube::write_log('trigger', $result->getBody());
+        }
+        catch (Exception $e) {
+            return PEAR::raiseError($e->getMessage());
+        }
 
-        return $result;
+        return true;
     }