diff --git a/lib/classes/event/calendar_event_updated.php b/lib/classes/event/calendar_event_updated.php
index fc0b3beb4bd..0a810c297c4 100644
--- a/lib/classes/event/calendar_event_updated.php
+++ b/lib/classes/event/calendar_event_updated.php
@@ -106,7 +106,7 @@ class calendar_event_updated extends base {
         if (empty($this->other['name'])) {
             throw new \coding_exception('The \'name\' value must be set in other.');
         }
-        if (empty($this->other['timestart'])) {
+        if (!isset($this->other['timestart'])) {
             throw new \coding_exception('The \'timestart\' value must be set in other.');
         }
     }