diff --git a/lib/upgrade.txt b/lib/upgrade.txt
index a244f7550b71c..93b1367d7d69f 100644
--- a/lib/upgrade.txt
+++ b/lib/upgrade.txt
@@ -10,6 +10,8 @@ Events and Logging:
 * Significant changes in Logging API. For upgrading existing events_trigger() and
   add_to_log() see http://docs.moodle.org/dev/Migrating_logging_calls_in_plugins
   For accessing logs from plugins see http://docs.moodle.org/dev/Migrating_log_access_in_reports
+* The validation of the following events is now stricter:
+    - \core\event\course_section_updated
 
 DEPRECATIONS:
 * $module uses in mod/xxx/version.php files is now deprecated. Please use $plugin instead. It will be removed in Moodle 2.10.