diff --git a/calendar/export_execute.php b/calendar/export_execute.php
index 7f195be..fa10bef 100644
--- a/calendar/export_execute.php
+++ b/calendar/export_execute.php
@@ -139,6 +139,8 @@ $events = calendar_get_events($timestart, $timeend, $users, $groups, array_keys(
 
 $ical = new iCalendar;
 $ical->add_property('method', 'PUBLISH');
+$ical->add_property('calscale', 'GREGORIAN');
+$ical->add_property('x-lotus-charset', 'UTF-8');
 foreach($events as $event) {
    if (!empty($event->modulename)) {
         $cm = get_coursemodule_from_instance($event->modulename, $event->instance);