diff -up openchange-openchange-2.3-VULCAN/libexchange2ical/exchange2ical_property.c.libical-3.0 openchange-openchange-2.3-VULCAN/libexchange2ical/exchange2ical_property.c
--- openchange-openchange-2.3-VULCAN/libexchange2ical/exchange2ical_property.c.libical-3.0	2017-11-08 14:45:06.494302213 +0100
+++ openchange-openchange-2.3-VULCAN/libexchange2ical/exchange2ical_property.c	2017-11-08 14:47:33.465300181 +0100
@@ -515,7 +515,7 @@ void ical_property_EXDATE(struct exchang
 				icalproperty_add_parameter(prop, tzid);
 			} else {
 				/*Get time from dtstart*/
-				icaltime.is_utc = 1;
+				icaltime.zone = icaltimezone_get_utc_timezone ();
 				if (exchange2ical->apptEndWhole){
 					dttime = get_icaltime_from_FILETIME_UTC(exchange2ical->apptStartWhole);
 					icaltime.hour   = dttime.hour;
diff -up openchange-openchange-2.3-VULCAN/libexchange2ical/exchange2ical_utils.c.libical-3.0 openchange-openchange-2.3-VULCAN/libexchange2ical/exchange2ical_utils.c
--- openchange-openchange-2.3-VULCAN/libexchange2ical/exchange2ical_utils.c.libical-3.0	2017-11-08 14:45:43.123301706 +0100
+++ openchange-openchange-2.3-VULCAN/libexchange2ical/exchange2ical_utils.c	2017-11-08 14:47:31.873300203 +0100
@@ -241,10 +241,9 @@ struct icaltimetype get_icaltimetype_fro
 	tt.minute = tm->tm_min;
 	tt.second = tm->tm_sec;
 
-	tt.is_utc      = 0;
 	tt.is_date     = 0;
 	tt.is_daylight = 0;
-	tt.zone        = 0;
+	tt.zone        = icaltimezone_get_utc_timezone ();
 
 	return tt;
 }
@@ -254,7 +253,6 @@ struct icaltimetype get_icaltimetype_fro
 	struct icaltimetype tt;
 	
 	tt = get_icaltimetype_from_tm(tm);
-	tt.is_utc      = 1;
 	
 	return tt;
 }
@@ -270,10 +268,8 @@ struct icaltimetype get_icaldate_from_tm
 	tt.minute = 0;
 	tt.second = 0;
 
-	tt.is_utc      = 1;
 	tt.is_date     = 1;
 	tt.is_daylight = 0;
-	tt.zone        = NULL;
 
 	return tt;
 }
@@ -313,7 +309,6 @@ struct icaltimetype get_icaltime_from_FI
 	tt.minute = tm->tm_min;                                                
 	tt.second = tm->tm_sec;
 	tt.is_date = 0;
-	tt.is_utc = 0;
 	tt.is_daylight = 0;
 	tt.zone = NULL;
 
@@ -339,9 +334,8 @@ struct icaltimetype get_icaltime_from_FI
 	tt.minute = tm->tm_min;                                                
 	tt.second = tm->tm_sec;
 	tt.is_date = 0;
-	tt.is_utc = 1;
 	tt.is_daylight = 0;
-	tt.zone = NULL;
+	tt.zone = icaltimezone_get_utc_timezone ();
 
 	return tt;
 }
@@ -371,9 +365,8 @@ struct icaltimetype get_icaldate_from_FI
 	tt.minute = 0;                                                
 	tt.second = 0;
 	tt.is_date = 1;
-	tt.is_utc = 1;
 	tt.is_daylight = 0;
-	tt.zone = NULL;
+	tt.zone = icaltimezone_get_utc_timezone ();
 
 	return tt;
 }
@@ -390,10 +383,9 @@ struct icaltimetype get_icaldate_from_Gl
 	tt.minute = 0;
 	tt.second = 0;
 
-	tt.is_utc      = 1;
 	tt.is_date     = 1;
 	tt.is_daylight = 0;
-	tt.zone        = NULL;
+	tt.zone        = icaltimezone_get_utc_timezone ();
 
 	return tt;
 }