diff --git a/course/lib.php b/course/lib.php
index 926c1ae1057..d55949add1a 100644
--- a/course/lib.php
+++ b/course/lib.php
@@ -3992,6 +3992,7 @@ function course_check_module_updates_since($cm, $from, $fileareas = array(), $fi
     // Check comments.
     if (plugin_supports('mod', $cm->modname, FEATURE_COMMENT) and (empty($filter) or in_array('comments', $filter))) {
         $updates->comments = (object) array('updated' => false);
+        require_once($CFG->dirroot . '/comment/lib.php');
         require_once($CFG->dirroot . '/comment/locallib.php');
         $manager = new comment_manager();
         $comments = $manager->get_component_comments_since($course, $context, $component, $from, $cm);