diff --git a/includes/Functions.php b/includes/Functions.php
index ee55e79..93a8e74 100644
--- a/includes/Functions.php
+++ b/includes/Functions.php
@@ -8,6 +8,12 @@
 
 class Functions
 {
+
+    public static function formatDateGMT($timestamp){
+		$date = new \DateTime(get_gmt_from_date(date('Y-m-d H:i:s', $timestamp)));
+		return $date->format('Ymd\THis\Z');
+	}
+
     public static function dateFormat(int $timestamp): string
     {
         return date_i18n(get_option('date_format'), $timestamp);
diff --git a/includes/ICS.php b/includes/ICS.php
index 597e2c9..e425fce 100644
--- a/includes/ICS.php
+++ b/includes/ICS.php
@@ -17,56 +17,32 @@ public static function generate(array &$booking, string $filename, string $recip
 		$output .= "BEGIN:VCALENDAR\r\n";
 		$output .= "VERSION:2.0\r\n";
 		$output .= "PRODID:-//rrze//rsvp//EN\r\n";
-		$output .= "CALSCALE:GREGORIAN\r\n";
-		$output .= "BEGIN:VTIMEZONE\r\n";
-		$output .= "TZID:Europe/Berlin\r\n";
-		$output .= "TZURL:http://tzurl.org/zoneinfo-outlook/Europe/Berlin\r\n";
-		$output .= "X-LIC-LOCATION:Europe/Berlin\r\n";
-		$output .= "BEGIN:DAYLIGHT\r\n";
-		$output .= "TZOFFSETFROM:+0100\r\n";
-		$output .= "TZOFFSETTO:+0200\r\n";
-		$output .= "TZNAME:CEST\r\n";
-		$output .= "DTSTART:19700329T020000\r\n";
-		$output .= "RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU\r\n";
-		$output .= "END:DAYLIGHT\r\n";
-		$output .= "BEGIN:STANDARD\r\n";
-		$output .= "TZOFFSETFROM:+0200\r\n";
-		$output .= "TZOFFSETTO:+0100\r\n";
-		$output .= "TZNAME:CET\r\n";
-		$output .= "DTSTART:19701025T030000\r\n";
-		$output .= "RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU\r\n";
-		$output .= "END:STANDARD\r\n";
-		$output .= "END:VTIMEZONE\r\n";
 		$output .= self::vevent($booking, $recipient);
 		$output .= "END:VCALENDAR\r\n";
 		return $output;
 	}
 
-	protected static function vevent(array &$booking, string $recipient = 'customer'): string
-	{
-		// $timezoneString = get_option('timezone_string');
-		$timezoneString = 'Europe/Berlin';
-		$dtstamp = date('Ymd\THis');
+	protected static function vevent(array &$booking, string $recipient = 'customer'): string {
+		$dtstamp = Functions::formatDateGMT(time());
 		$dtstampFormat = Functions::dateFormat(current_time('timestamp')) . ' ' . Functions::timeFormat(current_time('timestamp'));
-
 		$timestamp = date('ymdHi', $booking['start']);
-		$dtstamp = date('Ymd\THis');
-		$dtstart = date('Ymd\THis', $booking['start']);
-		$dtend = date('Ymd\THis', $booking['end']);
+		$dtstart = Functions::formatDateGMT($booking['start']);
+		$dtend = Functions::formatDateGMT($booking['end']);
 
 		$summary = $booking['room_name'];
-
 		$description = $booking['room_name'] . '\\n';
 		$description .= !empty($booking['seat_name']) ? $booking['seat_name'] . '\\n' : '';
+
 		if ($recipient == 'customer') {
 			$cancelUrl = Functions::bookingReplyUrl('cancel', sprintf('%s-%s-customer', $booking['id'], $booking['start']), $booking['id']);
 			$description .= "\\n\\n" . __('Cancel Booking', 'rrze-rsvp') . ':\\n' . $cancelUrl;	
 		}
+
 		$description .= "\\n\\n" . __('Generated', 'rrze-rsvp') . ': ' . $dtstampFormat;
 
 		$output = '';
-
 		$output .= "BEGIN:VEVENT\r\n";
+
 		if ($booking['status'] == 'cancelled'){
 			$output .= "METHOD:CANCEL\r\n";
 			$output .= "STATUS:CANCELLED\r\n";
@@ -75,10 +51,11 @@ protected static function vevent(array &$booking, string $recipient = 'customer'
 			$uid = md5($timestamp . date('ymdHi')) . "@rrze-rsvp";
 			update_post_meta($booking['id'], 'rrze-rsvp-booking-ics-uid', $uid);
 		}
+
 		$output .= "UID:" . $uid . "\r\n";
 		$output .= "DTSTAMP:" . $dtstamp . "\r\n";
-		$output .= "DTSTART;TZID=" . $timezoneString . ":" . $dtstart . "\r\n";
-		$output .= "DTEND;TZID=" . $timezoneString . ":" . $dtend . "\r\n";
+		$output .= "DTSTART:" . $dtstart . "\r\n";
+		$output .= "DTEND:" . $dtend . "\r\n";
 		$output .= "SUMMARY:" . $summary . "\r\n";
 		$output .= "DESCRIPTION:" . $description . "\r\n";
 		$output .= "END:VEVENT\r\n";
diff --git a/package.json b/package.json
index aa266fd..adb134f 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "rrze-rsvp",
-  "version": "2.6.23",
+  "version": "2.6.24",
   "description": "Platzbuchungssystem der FAU.",
   "main": "rrze-rsvp.php",
   "textdomain": "rrze-rsvp",
diff --git a/rrze-rsvp.php b/rrze-rsvp.php
index e9cdee9..e5940b5 100644
--- a/rrze-rsvp.php
+++ b/rrze-rsvp.php
@@ -4,7 +4,7 @@
 Plugin Name:     RRZE RSVP
 Plugin URI:      https://github.com/RRZE-Webteam/rrze-rsvp
 Description:     FAU Reservation Tool
-Version:         2.6.23
+Version:         2.6.24
 Author:          RRZE-Webteam
 Author URI:      https://blogs.fau.de/webworking/
 License:         GNU General Public License v2