From a7e796a66b589c34ae26037c9bd9d4e05cfa3b2c Mon Sep 17 00:00:00 2001
From: Ralf Becker <RalfBecker@outdoor-training.de>
Date: Wed, 10 Nov 2021 11:22:58 +0100
Subject: [PATCH] fix PHP 8.0 TypeError: Unsupported operand types:
 EGroupware\Api\DateTime - EGroupware\Api\DateTime

---
 calendar/inc/class.calendar_ical.inc.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/calendar/inc/class.calendar_ical.inc.php b/calendar/inc/class.calendar_ical.inc.php
index 330bcdafdc..08ecee35ec 100644
--- a/calendar/inc/class.calendar_ical.inc.php
+++ b/calendar/inc/class.calendar_ical.inc.php
@@ -600,8 +600,8 @@ class calendar_ical extends calendar_boupdate
 						if (empty($event['whole_day']))
 						{
 							// Hack for CalDAVTester to export duration instead of endtime
-							if ($tzid == 'UTC' && $event['end'] - $event['start'] <= 86400)
-								$attributes['duration'] = $event['end'] - $event['start'];
+							if ($tzid == 'UTC' && ($duration = Api\DateTime::to($event['end'], 'ts') - Api\DateTime::to($event['start'], 'ts')) <= 86400)
+								$attributes['duration'] = $duration;
 							else
 								$attributes['DTEND'] = self::getDateTime($event['end'],$tzid,$parameters['DTEND']);
 						}