Coursecatlib is only required for Moodle 3.5.x and lower

trigger/categories/lib.php

@@ -56,7 +56,10 @@ class categories extends base_automatic {
         $exclude = settings_manager::get_settings($triggerid, SETTINGS_TYPE_TRIGGER)['exclude'] && true;
 
         $categories = explode(',', $categories);
+        // Only require coursecatlib.php for Moodleversions before 3.6 .
+        if ($CFG->version < 2018120300) {
             require_once($CFG->libdir . '/coursecatlib.php');
+        }
         $categoryobjects = coursecat::get_many($categories);
         $allcategories = array();
         foreach ($categories as $category) {