--- ingo/lib/Storage/Vacation.php.orig	2018-08-06 13:48:42.690880615 +0200
+++ ingo/lib/Storage/Vacation.php	2018-07-23 14:17:08.454467809 +0200
@@ -137,7 +137,12 @@
      */
     public function getVacationExcludes()
     {
-        return $this->_excludes;
+        try {
+            return $GLOBALS['injector']->getInstance('Horde_Core_Hooks')
+                ->callHook('vacation_excludes', 'ingo', array(Ingo::getUser(), $this->_excludes));
+        } catch (Horde_Exception_HookNotSet $e) {
+            return $this->_excludes;
+        }
     }
 
     /**