diff -up evolution-ews-3.22.6/src/calendar/e-cal-backend-ews.c.free-busy-calendar evolution-ews-3.22.6/src/calendar/e-cal-backend-ews.c
--- evolution-ews-3.22.6/src/calendar/e-cal-backend-ews.c.free-busy-calendar	2017-02-06 14:06:19.000000000 +0100
+++ evolution-ews-3.22.6/src/calendar/e-cal-backend-ews.c	2017-05-24 15:38:44.189519188 +0200
@@ -43,6 +43,7 @@
 #include <calendar/gui/itip-utils.h>
 
 #include "server/e-source-ews-folder.h"
+#include "server/e-ews-calendar-utils.h"
 #include "server/e-ews-connection-utils.h"
 
 #include "utils/ews-camel-common.h"
@@ -87,6 +88,7 @@ struct _ECalBackendEwsPrivate {
 
 	guint subscription_key;
 	gboolean listen_notifications;
+	gboolean is_freebusy_calendar;
 };
 
 #define PRIV_LOCK(p)   (g_rec_mutex_lock (&(p)->rec_mutex))
@@ -735,7 +737,7 @@ cbews_listen_notifications_cb (ECalBacke
 		return;
 	}
 
-	cbews->priv->listen_notifications = camel_ews_settings_get_listen_notifications (ews_settings);
+	cbews->priv->listen_notifications = !cbews->priv->is_freebusy_calendar && camel_ews_settings_get_listen_notifications (ews_settings);
 	PRIV_UNLOCK (cbews->priv);
 
 	thread = g_thread_new (NULL, handle_notifications_thread, g_object_ref (cbews));
@@ -819,6 +821,7 @@ e_cal_backend_ews_open (ECalBackend *bac
 		extension_name = E_SOURCE_EXTENSION_EWS_FOLDER;
 		extension = e_source_get_extension (source, extension_name);
 		priv->folder_id = e_source_ews_folder_dup_id (extension);
+		priv->is_freebusy_calendar = g_strcmp0 (priv->folder_id, "freebusy-calendar") == 0;
 
 		priv->storage_path = g_build_filename (cache_dir, priv->folder_id, NULL);
 
@@ -848,11 +851,11 @@ e_cal_backend_ews_open (ECalBackend *bac
 		ret = cal_backend_ews_ensure_connected (cbews, cancellable, &error);
 
 	if (ret) {
-		e_cal_backend_set_writable (backend, TRUE);
+		e_cal_backend_set_writable (backend, !priv->is_freebusy_calendar);
 
 		PRIV_LOCK (priv);
 		if (priv->cnc != NULL) {
-			priv->listen_notifications = camel_ews_settings_get_listen_notifications (ews_settings);
+			priv->listen_notifications = !priv->is_freebusy_calendar && camel_ews_settings_get_listen_notifications (ews_settings);
 
 			if (priv->listen_notifications)
 				cbews_listen_notifications_cb (cbews, NULL, ews_settings);
@@ -3857,6 +3860,34 @@ cbews_forget_all_components (ECalBackend
 	g_slist_free_full (ids, (GDestroyNotify) e_cal_component_free_id);
 }
 
+static gboolean
+ews_freebusy_ecomp_changed (ECalComponent *ecomp,
+			    icalcomponent *vevent)
+{
+	icalcomponent *icomp;
+	gboolean changed = FALSE;
+
+	g_return_val_if_fail (vevent != NULL, FALSE);
+
+	if (!ecomp)
+		return TRUE;
+
+	icomp = e_cal_component_get_icalcomponent (ecomp);
+	if (!icomp)
+		return TRUE;
+
+	if (!changed)
+		changed = g_strcmp0 (icalcomponent_get_summary (icomp), icalcomponent_get_summary (vevent)) != 0;
+	if (!changed)
+		changed = g_strcmp0 (icalcomponent_get_location (icomp), icalcomponent_get_location (vevent)) != 0;
+	if (!changed)
+		changed = icaltime_compare (icalcomponent_get_dtstart (icomp), icalcomponent_get_dtstart (vevent)) != 0;
+	if (!changed)
+		changed = icaltime_compare (icalcomponent_get_dtend (icomp), icalcomponent_get_dtend (vevent)) != 0;
+
+	return changed;
+}
+
 static gpointer
 ews_start_sync_thread (gpointer data)
 {
@@ -3877,95 +3908,288 @@ ews_start_sync_thread (gpointer data)
 
 	cancellable = cal_backend_ews_ref_cancellable (cbews);
 
-	old_sync_state = g_strdup (e_cal_backend_store_get_key_value (priv->store, SYNC_KEY));
-	do {
-		EEwsAdditionalProps *add_props;
-		GCancellable *cancellable;
+	if (priv->is_freebusy_calendar) {
+		ESourceEwsFolder *ews_folder;
+		EEWSFreeBusyData fbdata;
+		GSList *free_busy = NULL, *link;
+		gboolean success;
+		time_t today;
+
+		ews_folder = e_source_get_extension (e_backend_get_source (E_BACKEND (cbews)), E_SOURCE_EXTENSION_EWS_FOLDER);
+
+		today = time_day_begin (time (NULL));
+
+		fbdata.period_start = time_add_week (today, -e_source_ews_folder_get_freebusy_weeks_before (ews_folder));
+		fbdata.period_end = time_day_end (time_add_week (today, e_source_ews_folder_get_freebusy_weeks_after (ews_folder)));
+		fbdata.user_mails = g_slist_prepend (NULL, e_source_ews_folder_dup_foreign_mail (ews_folder));
+
+		success = e_ews_connection_get_free_busy_sync (priv->cnc, G_PRIORITY_DEFAULT,
+			e_ews_cal_utils_prepare_free_busy_request, &fbdata,
+			&free_busy, cancellable, &error);
+
+		if (success) {
+			icaltimezone *utc_zone = icaltimezone_get_utc_timezone ();
+			GSList *ids;
+			GHashTable *known;
+			GHashTableIter iter;
+			gpointer key;
+
+			known = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
+
+			ids = e_cal_backend_store_get_component_ids (priv->store);
+			for (link = ids; link; link = g_slist_next (link)) {
+				ECalComponentId *id = link->data;
 
-		includes_last_item = TRUE;
+				if (id && id->uid && *id->uid)
+					g_hash_table_insert (known, g_strdup (id->uid), NULL);
+			}
+			g_slist_free_full (ids, (GDestroyNotify) e_cal_component_free_id);
 
-		add_props = e_ews_additional_props_new ();
-		add_props->field_uri = g_strdup ("item:ItemClass");
+			for (link = free_busy; link; link = g_slist_next (link)) {
+				icalcomponent *fbcomp = link->data;
+				icalproperty *fbprop;
+				icalparameter *param;
+				struct icalperiodtype fb;
+				icalparameter_fbtype fbtype;
+
+				if (!fbcomp || icalcomponent_isa (fbcomp) != ICAL_VFREEBUSY_COMPONENT)
+					continue;
+
+				for (fbprop = icalcomponent_get_first_property (fbcomp, ICAL_FREEBUSY_PROPERTY);
+				     fbprop;
+				     fbprop = icalcomponent_get_next_property (fbcomp, ICAL_FREEBUSY_PROPERTY)) {
+					icalcomponent *vevent;
+					const gchar *id, *summary, *location;
+
+					param = icalproperty_get_first_parameter (fbprop, ICAL_FBTYPE_PARAMETER);
+					if (!param)
+						continue;
+
+					fbtype = icalparameter_get_fbtype (param);
+
+					if (fbtype != ICAL_FBTYPE_FREE &&
+					    fbtype != ICAL_FBTYPE_BUSY &&
+					    fbtype != ICAL_FBTYPE_BUSYUNAVAILABLE &&
+					    fbtype != ICAL_FBTYPE_BUSYTENTATIVE)
+						continue;
+
+					fb = icalproperty_get_freebusy (fbprop);
+					id = icalproperty_get_parameter_as_string (fbprop, "X-EWS-ID");
+					summary = icalproperty_get_parameter_as_string (fbprop, "X-SUMMARY");
+					location = icalproperty_get_parameter_as_string (fbprop, "X-LOCATION");
 
-		cancellable = cal_backend_ews_ref_cancellable (cbews);
+					vevent = icalcomponent_new_vevent ();
 
-		ret = e_ews_connection_sync_folder_items_sync (
-			priv->cnc,
-			EWS_PRIORITY_MEDIUM,
-			old_sync_state,
-			priv->folder_id,
-			"IdOnly",
-			add_props,
-			EWS_MAX_FETCH_COUNT,
-			&new_sync_state,
-			&includes_last_item,
-			&items_created,
-			&items_updated,
-			&items_deleted,
-			cancellable,
-			&error);
+					if (id && *id) {
+						icalcomponent_set_uid (vevent, id);
+					} else {
+						gchar *uid;
 
-		e_ews_additional_props_free (add_props);
-		g_clear_object (&cancellable);
-		g_free (old_sync_state);
-		old_sync_state = NULL;
+						uid = g_strdup_printf ("%s-%s-%d",
+							icaltime_as_ical_string (fb.start),
+							icaltime_as_ical_string (fb.end),
+							(gint) fbtype);
+
+						icalcomponent_set_uid (vevent, uid);
+
+						g_free (uid);
+					}
 
-		if (!ret) {
-			if (g_error_matches (error, EWS_CONNECTION_ERROR, EWS_CONNECTION_ERROR_INVALIDSYNCSTATEDATA)) {
-				g_clear_error (&error);
-				e_cal_backend_store_put_key_value (priv->store, SYNC_KEY, NULL);
-				cbews_forget_all_components (cbews);
-
-				if (!e_ews_connection_sync_folder_items_sync (
-							priv->cnc,
-							EWS_PRIORITY_MEDIUM,
-							NULL,
-							priv->folder_id,
-							"IdOnly",
-							NULL,
-							EWS_MAX_FETCH_COUNT,
-							&new_sync_state,
-							&includes_last_item,
-							&items_created,
-							&items_updated,
-							&items_deleted,
-							cancellable,
-							&error)) {
-					if (!g_error_matches (
-							error,
-							EWS_CONNECTION_ERROR,
-							EWS_CONNECTION_ERROR_AUTHENTICATION_FAILED)) {
-						e_cal_backend_set_writable (E_CAL_BACKEND (cbews), TRUE);
-						break;
+					fb.start.zone = utc_zone;
+					fb.start.is_utc = 1;
+					fb.end.zone = utc_zone;
+					fb.end.is_utc = 1;
+
+					icalcomponent_set_dtstart (vevent, fb.start);
+					icalcomponent_set_dtend (vevent, fb.end);
+
+					icalcomponent_add_property (vevent, icalproperty_new_created (icaltime_current_time_with_zone (utc_zone)));
+
+					if (fbtype == ICAL_FBTYPE_FREE) {
+						icalcomponent_set_summary (vevent, C_("FreeBusyType", "Free"));
+						icalcomponent_add_property (vevent, icalproperty_new_transp (ICAL_TRANSP_TRANSPARENT));
+					} else if (fbtype == ICAL_FBTYPE_BUSY) {
+						icalcomponent_set_summary (vevent, C_("FreeBusyType", "Busy"));
+					} else if (fbtype == ICAL_FBTYPE_BUSYUNAVAILABLE) {
+						icalcomponent_set_summary (vevent, C_("FreeBusyType", "Out of Office"));
+					} else if (fbtype == ICAL_FBTYPE_BUSYTENTATIVE) {
+						icalcomponent_set_summary (vevent, C_("FreeBusyType", "Tentative"));
+					}
+
+					if (summary && *summary)
+						icalcomponent_set_summary (vevent, summary);
+
+					if (location && *location)
+						icalcomponent_set_location (vevent, location);
+
+					PRIV_LOCK (priv);
+					if (g_hash_table_remove (known, icalcomponent_get_uid (vevent))) {
+						ECalComponent *ecomp = g_hash_table_lookup (priv->item_id_hash, icalcomponent_get_uid (vevent));
+
+						g_object_ref (ecomp);
+
+						PRIV_UNLOCK (priv);
+
+						if (ews_freebusy_ecomp_changed (ecomp, vevent)) {
+							ECalComponent *new_ecomp;
+							gchar *uid = g_strdup (icalcomponent_get_uid (vevent));
+
+							new_ecomp = e_cal_component_new_from_icalcomponent (vevent);
+							if (new_ecomp) {
+								PRIV_LOCK (priv);
+								g_hash_table_insert (priv->item_id_hash, uid, g_object_ref (new_ecomp));
+								PRIV_UNLOCK (priv);
+
+								put_component_to_store (cbews, new_ecomp);
+								e_cal_backend_notify_component_modified (E_CAL_BACKEND (cbews), ecomp, new_ecomp);
+
+								g_object_unref (new_ecomp);
+							} else {
+								g_free (uid);
+							}
+						} else {
+							icalcomponent_free (vevent);
+						}
+
+						g_clear_object (&ecomp);
+					} else {
+						ECalComponent *ecomp;
+						gchar *uid = g_strdup (icalcomponent_get_uid (vevent));
+
+						ecomp = e_cal_component_new_from_icalcomponent (vevent);
+						if (ecomp)
+							g_hash_table_insert (priv->item_id_hash, uid, g_object_ref (ecomp));
+						else
+							g_free (uid);
+
+						PRIV_UNLOCK (priv);
+
+						if (ecomp) {
+							put_component_to_store (cbews, ecomp);
+							e_cal_backend_notify_component_created (E_CAL_BACKEND (cbews), ecomp);
+						}
+
+						g_clear_object (&ecomp);
 					}
 				}
-			} else {
-				break;
 			}
+
+			g_hash_table_iter_init (&iter, known);
+			while (g_hash_table_iter_next (&iter, &key, NULL)) {
+				ECalComponentId id = { 0 };
+
+				id.uid = key;
+				id.rid = NULL;
+
+				if (e_cal_backend_store_remove_component (priv->store, id.uid, id.rid)) {
+					e_cal_backend_notify_component_removed (E_CAL_BACKEND (cbews), &id, NULL, NULL);
+
+					PRIV_LOCK (priv);
+					g_hash_table_remove (priv->item_id_hash, id.uid);
+					PRIV_UNLOCK (priv);
+				}
+			}
+
+			g_hash_table_destroy (known);
+		} else if (g_error_matches (error, EWS_CONNECTION_ERROR, EWS_CONNECTION_ERROR_NOFREEBUSYACCESS)) {
+			cbews_forget_all_components (cbews);
+			e_cal_backend_notify_error (E_CAL_BACKEND (cbews), error->message);
+			g_clear_error (&error);
 		}
 
-		ret = cal_backend_ews_process_folder_items (
-				cbews,
-				new_sync_state,
-				items_created,
-				items_updated,
-				items_deleted);
+		g_slist_free_full (free_busy, (GDestroyNotify) icalcomponent_free);
+		g_slist_free_full (fbdata.user_mails, g_free);
+	} else {
+		old_sync_state = g_strdup (e_cal_backend_store_get_key_value (priv->store, SYNC_KEY));
+		do {
+			EEwsAdditionalProps *add_props;
+			GCancellable *cancellable;
+
+			includes_last_item = TRUE;
 
-		if (!ret)
-			break;
+			add_props = e_ews_additional_props_new ();
+			add_props->field_uri = g_strdup ("item:ItemClass");
 
-		g_slist_free_full (items_created, g_object_unref);
-		g_slist_free_full (items_updated, g_object_unref);
-		g_slist_free_full (items_deleted, g_free);
-		items_created = NULL;
-		items_updated = NULL;
-		items_deleted = NULL;
-
-		e_cal_backend_store_put_key_value (priv->store, SYNC_KEY, new_sync_state);
-
-		old_sync_state = new_sync_state;
-		new_sync_state = NULL;
-	} while (!includes_last_item);
+			cancellable = cal_backend_ews_ref_cancellable (cbews);
+
+			ret = e_ews_connection_sync_folder_items_sync (
+				priv->cnc,
+				EWS_PRIORITY_MEDIUM,
+				old_sync_state,
+				priv->folder_id,
+				"IdOnly",
+				add_props,
+				EWS_MAX_FETCH_COUNT,
+				&new_sync_state,
+				&includes_last_item,
+				&items_created,
+				&items_updated,
+				&items_deleted,
+				cancellable,
+				&error);
+
+			e_ews_additional_props_free (add_props);
+			g_clear_object (&cancellable);
+			g_free (old_sync_state);
+			old_sync_state = NULL;
+
+			if (!ret) {
+				if (g_error_matches (error, EWS_CONNECTION_ERROR, EWS_CONNECTION_ERROR_INVALIDSYNCSTATEDATA)) {
+					g_clear_error (&error);
+					e_cal_backend_store_put_key_value (priv->store, SYNC_KEY, NULL);
+					cbews_forget_all_components (cbews);
+
+					if (!e_ews_connection_sync_folder_items_sync (
+								priv->cnc,
+								EWS_PRIORITY_MEDIUM,
+								NULL,
+								priv->folder_id,
+								"IdOnly",
+								NULL,
+								EWS_MAX_FETCH_COUNT,
+								&new_sync_state,
+								&includes_last_item,
+								&items_created,
+								&items_updated,
+								&items_deleted,
+								cancellable,
+								&error)) {
+						if (!g_error_matches (
+								error,
+								EWS_CONNECTION_ERROR,
+								EWS_CONNECTION_ERROR_AUTHENTICATION_FAILED)) {
+							e_cal_backend_set_writable (E_CAL_BACKEND (cbews), TRUE);
+							break;
+						}
+					}
+				} else {
+					break;
+				}
+			}
+
+			ret = cal_backend_ews_process_folder_items (
+					cbews,
+					new_sync_state,
+					items_created,
+					items_updated,
+					items_deleted);
+
+			if (!ret)
+				break;
+
+			g_slist_free_full (items_created, g_object_unref);
+			g_slist_free_full (items_updated, g_object_unref);
+			g_slist_free_full (items_deleted, g_free);
+			items_created = NULL;
+			items_updated = NULL;
+			items_deleted = NULL;
+
+			e_cal_backend_store_put_key_value (priv->store, SYNC_KEY, new_sync_state);
+
+			old_sync_state = new_sync_state;
+			new_sync_state = NULL;
+		} while (!includes_last_item);
+	}
 
 	ews_refreshing_dec (cbews);
 
@@ -4163,7 +4387,7 @@ e_cal_backend_ews_get_free_busy (ECalBac
 	ECalBackendEwsPrivate *priv = cbews->priv;
 	GError *error = NULL;
 	EwsCalendarAsyncData *free_busy_data;
-	EwsCalendarConvertData convert_data = { 0 };
+	EEWSFreeBusyData fbdata = { 0 };
 	GSList *users_copy = NULL;
 
 	/* make sure we're not offline */
@@ -4193,15 +4417,15 @@ e_cal_backend_ews_get_free_busy (ECalBac
 	free_busy_data->context = context;
 	free_busy_data->users = users_copy;
 
-	convert_data.users = users_copy;
-	convert_data.start = start;
-	convert_data.end = end;
+	fbdata.period_start = start;
+	fbdata.period_end = end;
+	fbdata.user_mails = users_copy;
 
 	e_ews_connection_get_free_busy (
 		priv->cnc,
 		EWS_PRIORITY_MEDIUM,
-		e_cal_backend_ews_prepare_free_busy_request,
-		&convert_data,
+		e_ews_cal_utils_prepare_free_busy_request,
+		&fbdata,
 		cancellable,
 		ews_cal_get_free_busy_cb,
 		free_busy_data);
diff -up evolution-ews-3.22.6/src/calendar/e-cal-backend-ews-utils.c.free-busy-calendar evolution-ews-3.22.6/src/calendar/e-cal-backend-ews-utils.c
--- evolution-ews-3.22.6/src/calendar/e-cal-backend-ews-utils.c.free-busy-calendar	2016-12-16 12:36:06.000000000 +0100
+++ evolution-ews-3.22.6/src/calendar/e-cal-backend-ews-utils.c	2017-05-24 15:38:44.189519188 +0200
@@ -42,6 +42,7 @@
 #include <libecal/libecal.h>
 #include <libsoup/soup-misc.h>
 
+#include "server/e-ews-calendar-utils.h"
 #include "server/e-ews-connection.h"
 #include "server/e-ews-message.h"
 #include "server/e-ews-item-change.h"
@@ -338,49 +339,6 @@ ews_set_alarm (ESoapMessage *msg,
 
 }
 
-void
-ewscal_set_time (ESoapMessage *msg,
-                 const gchar *name,
-                 icaltimetype *t,
-                 gboolean with_timezone)
-{
-	gchar *str;
-	gchar *tz_ident = NULL;
-
-	if (with_timezone) {
-		if (t->is_utc || !t->zone || t->zone == icaltimezone_get_utc_timezone ()) {
-			tz_ident = g_strdup ("Z");
-		} else {
-			gint offset, is_daylight, hrs, mins;
-
-			offset = icaltimezone_get_utc_offset (
-				icaltimezone_get_utc_timezone (), t, &is_daylight);
-
-			offset = offset * (-1);
-			hrs = offset / 60;
-			mins = offset % 60;
-
-			if (hrs < 0)
-				hrs *= -1;
-			if (mins < 0)
-				mins *= -1;
-
-			tz_ident = g_strdup_printf ("%s%02d:%02d", offset > 0 ? "+" : "-", hrs, mins);
-		}
-	}
-
-	str = g_strdup_printf (
-		"%04d-%02d-%02dT%02d:%02d:%02d%s",
-		t->year, t->month, t->day,
-		t->hour, t->minute, t->second,
-		tz_ident ? tz_ident : "");
-
-	e_ews_message_write_string_parameter (msg, name, NULL, str);
-
-	g_free (tz_ident);
-	g_free (str);
-}
-
 static void
 ewscal_set_date (ESoapMessage *msg,
                  const gchar *name,
@@ -713,136 +671,6 @@ ewscal_set_meeting_timezone (ESoapMessag
 	e_soap_message_end_element (msg); /* "MeetingTimeZone" */
 }
 
-static void
-ewscal_add_availability_rrule (ESoapMessage *msg,
-                               icalproperty *prop)
-{
-	struct icalrecurrencetype recur = icalproperty_get_rrule (prop);
-	gchar buffer[16];
-	gint dayorder;
-
-	dayorder = icalrecurrencetype_day_position (recur.by_day[0]);
-	dayorder = dayorder % 5;
-	if (dayorder < 0)
-		dayorder += 5;
-	dayorder += 1;
-
-	/* expected value is 1..5, inclusive */
-	snprintf (buffer, 16, "%d", dayorder);
-	e_ews_message_write_string_parameter (msg, "DayOrder", NULL, buffer);
-
-	snprintf (buffer, 16, "%d", recur.by_month[0]);
-	e_ews_message_write_string_parameter (msg, "Month", NULL, buffer);
-
-	e_ews_message_write_string_parameter (msg, "DayOfWeek", NULL, number_to_weekday (icalrecurrencetype_day_day_of_week (recur.by_day[0])));
-}
-
-static void
-ewscal_add_availability_default_timechange (ESoapMessage *msg)
-{
-
-	e_soap_message_start_element (msg, "StandardTime", NULL, NULL);
-	e_ews_message_write_string_parameter (msg, "Bias", NULL, "0");
-	e_ews_message_write_string_parameter (msg, "Time", NULL, "00:00:00");
-	e_ews_message_write_string_parameter (msg, "DayOrder", NULL, "0");
-	e_ews_message_write_string_parameter (msg, "Month", NULL, "0");
-	e_ews_message_write_string_parameter (msg, "DayOfWeek", NULL, "Sunday");
-	e_soap_message_end_element (msg);
-
-	e_soap_message_start_element (msg, "DaylightTime", NULL, NULL);
-	e_ews_message_write_string_parameter (msg, "Bias", NULL, "0");
-	e_ews_message_write_string_parameter (msg, "Time", NULL, "00:00:00");
-	e_ews_message_write_string_parameter (msg, "DayOrder", NULL, "0");
-	e_ews_message_write_string_parameter (msg, "Month", NULL, "0");
-	e_ews_message_write_string_parameter (msg, "DayOfWeek", NULL, "Sunday");
-	e_soap_message_end_element (msg);
-}
-
-static void
-ewscal_add_availability_timechange (ESoapMessage *msg,
-                                    icalcomponent *comp,
-                                    gint baseoffs)
-{
-	gchar buffer[16];
-	icalproperty *prop;
-	struct icaltimetype dtstart;
-	gint utcoffs;
-
-	/* Calculate zone Offset from BaseOffset */
-	prop = icalcomponent_get_first_property (comp, ICAL_TZOFFSETTO_PROPERTY);
-	if (prop) {
-		utcoffs = -icalproperty_get_tzoffsetto (prop) / 60;
-		utcoffs -= baseoffs;
-		snprintf (buffer, 16, "%d", utcoffs);
-		e_ews_message_write_string_parameter (msg, "Bias", NULL, buffer);
-	}
-
-	prop = icalcomponent_get_first_property (comp, ICAL_DTSTART_PROPERTY);
-	if (prop) {
-		dtstart = icalproperty_get_dtstart (prop);
-		snprintf (buffer, 16, "%02d:%02d:%02d", dtstart.hour, dtstart.minute, dtstart.second);
-		e_ews_message_write_string_parameter (msg, "Time", NULL, buffer);
-	}
-
-	prop = icalcomponent_get_first_property (comp, ICAL_RRULE_PROPERTY);
-	if (prop)
-		ewscal_add_availability_rrule (msg, prop);
-}
-
-void
-ewscal_set_availability_timezone (ESoapMessage *msg,
-                                  icaltimezone *icaltz)
-{
-	icalcomponent *comp;
-	icalproperty *prop;
-	icalcomponent *xstd, *xdaylight;
-	gint std_utcoffs;
-	gchar *offset;
-
-	if (!icaltz)
-		return;
-
-	comp = icaltimezone_get_component (icaltz);
-
-	xstd = icalcomponent_get_first_component (comp, ICAL_XSTANDARD_COMPONENT);
-	xdaylight = icalcomponent_get_first_component (comp, ICAL_XDAYLIGHT_COMPONENT);
-
-	/*TimeZone is the root element of GetUserAvailabilityRequest*/
-	e_soap_message_start_element (msg, "TimeZone", NULL, NULL);
-
-	/* Fetch the timezone offsets for the standard (or only) zone.
-	 * Negate it, because Exchange does it backwards */
-	if (xstd) {
-		prop = icalcomponent_get_first_property (xstd, ICAL_TZOFFSETTO_PROPERTY);
-		std_utcoffs = -icalproperty_get_tzoffsetto (prop) / 60;
-	} else
-		std_utcoffs = 0;
-
-	/* This is the overall BaseOffset tag, which the Standard and Daylight
-	 * zones are offset from. It's redundant, but Exchange always sets it
-	 * to the offset of the Standard zone, and the Offset in the Standard
-	 * zone to zero. So try to avoid problems by doing the same. */
-	offset = g_strdup_printf ("%d", std_utcoffs);
-	e_ews_message_write_string_parameter (msg, "Bias", NULL, offset);
-	g_free (offset);
-
-	if (xdaylight) {
-		/* Standard */
-		e_soap_message_start_element (msg, "StandardTime", NULL, NULL);
-		ewscal_add_availability_timechange (msg, xstd, std_utcoffs);
-		e_soap_message_end_element (msg); /* "StandardTime" */
-
-		/* DayLight */
-		e_soap_message_start_element (msg, "DaylightTime", NULL, NULL);
-		ewscal_add_availability_timechange (msg, xdaylight, std_utcoffs);
-		e_soap_message_end_element (msg); /* "DaylightTime" */
-	} else
-		/* Set default values*/
-		ewscal_add_availability_default_timechange (msg);
-
-	e_soap_message_end_element (msg); /* "TimeZone" */
-}
-
 void
 ewscal_set_reccurence (ESoapMessage *msg,
                        icalproperty *rrule,
@@ -1321,8 +1149,8 @@ convert_vevent_calcomp_to_xml (ESoapMess
 			ical_location_end);
 	}
 
-	ewscal_set_time (msg, "Start", &dtstart, FALSE);
-	ewscal_set_time (msg, "End", &dtend, FALSE);
+	e_ews_cal_utils_set_time (msg, "Start", &dtstart, FALSE);
+	e_ews_cal_utils_set_time (msg, "End", &dtend, FALSE);
 	/* We have to do the time zone(s) later, or the server rejects the request */
 
 	/* All day event ? */
@@ -1424,7 +1252,7 @@ convert_vtodo_calcomp_to_xml (ESoapMessa
 	prop = icalcomponent_get_first_property (icalcomp, ICAL_DUE_PROPERTY);
 	if (prop) {
 		dt = icalproperty_get_due (prop);
-		ewscal_set_time (msg, "DueDate", &dt, TRUE);
+		e_ews_cal_utils_set_time (msg, "DueDate", &dt, TRUE);
 	}
 
 	prop = icalcomponent_get_first_property (icalcomp, ICAL_PERCENTCOMPLETE_PROPERTY);
@@ -1437,7 +1265,7 @@ convert_vtodo_calcomp_to_xml (ESoapMessa
 	prop = icalcomponent_get_first_property (icalcomp, ICAL_DTSTART_PROPERTY);
 	if (prop) {
 		dt = icalproperty_get_dtstart (prop);
-		ewscal_set_time (msg, "StartDate", &dt, TRUE);
+		e_ews_cal_utils_set_time (msg, "StartDate", &dt, TRUE);
 	}
 
 	prop = icalcomponent_get_first_property (icalcomp, ICAL_STATUS_PROPERTY);
@@ -1751,13 +1579,13 @@ convert_vevent_component_to_updatexml (E
 
 	if (dt_start_changed) {
 		e_ews_message_start_set_item_field (msg, "Start", "calendar","CalendarItem");
-		ewscal_set_time (msg, "Start", &dtstart, FALSE);
+		e_ews_cal_utils_set_time (msg, "Start", &dtstart, FALSE);
 		e_ews_message_end_set_item_field (msg);
 	}
 
 	if (dt_end_changed) {
 		e_ews_message_start_set_item_field (msg, "End", "calendar", "CalendarItem");
-		ewscal_set_time (msg, "End", &dtend, FALSE);
+		e_ews_cal_utils_set_time (msg, "End", &dtend, FALSE);
 		e_ews_message_end_set_item_field (msg);
 	}
 
@@ -1915,7 +1743,7 @@ convert_vtodo_component_to_updatexml (ES
 	if (prop) {
 		dt = icalproperty_get_due (prop);
 		e_ews_message_start_set_item_field (msg, "DueDate", "task", "Task");
-		ewscal_set_time (msg, "DueDate", &dt, TRUE);
+		e_ews_cal_utils_set_time (msg, "DueDate", &dt, TRUE);
 		e_ews_message_end_set_item_field (msg);
 	} else {
 		e_ews_message_add_delete_item_field (msg, "DueDate", "task");
@@ -1934,7 +1762,7 @@ convert_vtodo_component_to_updatexml (ES
 	if (prop) {
 		dt = icalproperty_get_dtstart (prop);
 		e_ews_message_start_set_item_field (msg, "StartDate", "task", "Task");
-		ewscal_set_time (msg, "StartDate", &dt, TRUE);
+		e_ews_cal_utils_set_time (msg, "StartDate", &dt, TRUE);
 		e_ews_message_end_set_item_field (msg);
 	} else {
 		e_ews_message_add_delete_item_field (msg, "StartDate", "task");
@@ -2100,49 +1928,6 @@ e_cal_backend_ews_clear_reminder_is_set
 }
 
 void
-e_cal_backend_ews_prepare_free_busy_request (ESoapMessage *msg,
-					     gpointer user_data)
-{
-	EwsCalendarConvertData *convert_data = user_data;
-	GSList *addr;
-	icaltimetype t_start, t_end;
-	icaltimezone *utc_zone = icaltimezone_get_utc_timezone ();
-
-	ewscal_set_availability_timezone (msg, utc_zone);
-
-	e_soap_message_start_element (msg, "MailboxDataArray", "messages", NULL);
-
-	for (addr = convert_data->users; addr; addr = addr->next) {
-		e_soap_message_start_element (msg, "MailboxData", NULL, NULL);
-
-		e_soap_message_start_element (msg, "Email", NULL, NULL);
-		e_ews_message_write_string_parameter (msg, "Address", NULL, addr->data);
-		e_soap_message_end_element (msg); /* "Email" */
-
-		e_ews_message_write_string_parameter (msg, "AttendeeType", NULL, "Required");
-		e_ews_message_write_string_parameter (msg, "ExcludeConflicts", NULL, "false");
-
-		e_soap_message_end_element (msg); /* "MailboxData" */
-	}
-
-	e_soap_message_end_element (msg); /* "MailboxDataArray" */
-
-	e_soap_message_start_element (msg, "FreeBusyViewOptions", NULL, NULL);
-
-	e_soap_message_start_element (msg, "TimeWindow", NULL, NULL);
-	t_start = icaltime_from_timet_with_zone (convert_data->start, 0, utc_zone);
-	t_end = icaltime_from_timet_with_zone (convert_data->end, 0, utc_zone);
-	ewscal_set_time (msg, "StartTime", &t_start, FALSE);
-	ewscal_set_time (msg, "EndTime", &t_end, FALSE);
-	e_soap_message_end_element (msg); /* "TimeWindow" */
-
-	e_ews_message_write_string_parameter (msg, "MergedFreeBusyIntervalInMinutes", NULL, "60");
-	e_ews_message_write_string_parameter (msg, "RequestedView", NULL, "DetailedMerged");
-
-	e_soap_message_end_element (msg); /* "FreeBusyViewOptions" */
-}
-
-void
 e_cal_backend_ews_prepare_set_free_busy_status (ESoapMessage *msg,
 						gpointer user_data)
 {
diff -up evolution-ews-3.22.6/src/calendar/e-cal-backend-ews-utils.h.free-busy-calendar evolution-ews-3.22.6/src/calendar/e-cal-backend-ews-utils.h
--- evolution-ews-3.22.6/src/calendar/e-cal-backend-ews-utils.h.free-busy-calendar	2014-05-28 13:24:49.000000000 +0200
+++ evolution-ews-3.22.6/src/calendar/e-cal-backend-ews-utils.h	2017-05-24 15:38:44.189519188 +0200
@@ -57,10 +57,8 @@ typedef struct {
 const gchar *e_ews_collect_organizer (icalcomponent *comp);
 void e_ews_collect_attendees (icalcomponent *comp, GSList **required, GSList **optional, GSList **resource);
 
-void ewscal_set_time (ESoapMessage *msg, const gchar *name, icaltimetype *t, gboolean with_timezone);
 void ewscal_set_timezone (ESoapMessage *msg, const gchar *name, EEwsCalendarTimeZoneDefinition *tzd);
 void ewscal_set_meeting_timezone (ESoapMessage *msg, icaltimezone *icaltz);
-void ewscal_set_availability_timezone (ESoapMessage *msg, icaltimezone *icaltz);
 void ewscal_set_reccurence (ESoapMessage *msg, icalproperty *rrule, icaltimetype *dtstart);
 void ewscal_set_reccurence_exceptions (ESoapMessage *msg, icalcomponent *comp);
 void ewscal_get_attach_differences (const GSList *original, const GSList *modified, GSList **removed, GSList **added);
@@ -77,7 +75,6 @@ void e_cal_backend_ews_unref_windows_zon
 void e_cal_backend_ews_convert_calcomp_to_xml (ESoapMessage *msg, gpointer user_data);
 void e_cal_backend_ews_convert_component_to_updatexml (ESoapMessage *msg, gpointer user_data);
 void e_cal_backend_ews_clear_reminder_is_set (ESoapMessage *msg, gpointer user_data);
-void e_cal_backend_ews_prepare_free_busy_request (ESoapMessage *msg, gpointer user_data);
 void e_cal_backend_ews_prepare_set_free_busy_status (ESoapMessage *msg,gpointer user_data);
 void e_cal_backend_ews_prepare_accept_item_request (ESoapMessage *msg, gpointer user_data);
 
diff -up evolution-ews-3.22.6/src/configuration/e-ews-subscribe-foreign-folder.c.free-busy-calendar evolution-ews-3.22.6/src/configuration/e-ews-subscribe-foreign-folder.c
--- evolution-ews-3.22.6/src/configuration/e-ews-subscribe-foreign-folder.c.free-busy-calendar	2014-11-19 19:06:36.000000000 +0100
+++ evolution-ews-3.22.6/src/configuration/e-ews-subscribe-foreign-folder.c	2017-05-24 15:38:44.190519183 +0200
@@ -34,6 +34,8 @@
 #include "camel/camel-ews-store-summary.h"
 #include "camel/camel-ews-utils.h"
 
+#include "server/e-ews-calendar-utils.h"
+
 #include "e-ews-config-utils.h"
 #include "e-ews-search-user.h"
 #include "e-ews-subscribe-foreign-folder.h"
@@ -344,24 +346,53 @@ check_foreign_folder_thread (GObject *wi
 		return;
 	}
 
-	fid.id = (gchar *) (cffd->use_foldername ? cffd->use_foldername : cffd->orig_foldername);
-	fid.change_key = NULL;
-	fid.is_distinguished_id = cffd->use_foldername != NULL;
-
-	if (!e_ews_connection_get_folder_info_sync (conn, G_PRIORITY_DEFAULT,
-		cffd->email, &fid, &folder, cancellable, &local_error)) {
-		if (g_error_matches (local_error, EWS_CONNECTION_ERROR, EWS_CONNECTION_ERROR_ITEMNOTFOUND) ||
-		    g_error_matches (local_error, EWS_CONNECTION_ERROR, EWS_CONNECTION_ERROR_FOLDERNOTFOUND)) {
-			g_clear_error (&local_error);
-			local_error = g_error_new (
-				EWS_CONNECTION_ERROR, EWS_CONNECTION_ERROR_FOLDERNOTFOUND,
-				_("Folder '%s' not found. Either it does not exist or you do not have permission to access it."),
-				cffd->orig_foldername);
+	if (g_strcmp0 (cffd->use_foldername, "freebusy-calendar") == 0) {
+		EEWSFreeBusyData fbdata;
+		GSList *free_busy = NULL;
+		gboolean success;
+
+		fbdata.period_start = time (NULL);
+		fbdata.period_end = fbdata.period_start + (60 * 60);
+		fbdata.user_mails = g_slist_prepend (NULL, cffd->email);
+
+		success = e_ews_connection_get_free_busy_sync (conn, G_PRIORITY_DEFAULT,
+			e_ews_cal_utils_prepare_free_busy_request, &fbdata,
+			&free_busy, cancellable, perror);
+
+		g_slist_free_full (free_busy, (GDestroyNotify) icalcomponent_free);
+		g_slist_free (fbdata.user_mails);
+
+		if (!success) {
+			g_object_unref (conn);
+			return;
 		}
 
-		g_propagate_error (perror, local_error);
-		g_object_unref (conn);
-		return;
+		folder = g_object_new (E_TYPE_EWS_FOLDER, NULL);
+		e_ews_folder_set_id (folder, e_ews_folder_id_new (cffd->use_foldername, NULL, FALSE));
+		/* Translators: This is used as a calendar name; it constructs "User Name - Availability" string shown in UI */
+		e_ews_folder_set_name (folder, _("Availability"));
+		e_ews_folder_set_folder_type (folder, E_EWS_FOLDER_TYPE_CALENDAR);
+		e_ews_folder_set_foreign_mail (folder, cffd->email);
+	} else {
+		fid.id = (gchar *) (cffd->use_foldername ? cffd->use_foldername : cffd->orig_foldername);
+		fid.change_key = NULL;
+		fid.is_distinguished_id = cffd->use_foldername != NULL;
+
+		if (!e_ews_connection_get_folder_info_sync (conn, G_PRIORITY_DEFAULT,
+			cffd->email, &fid, &folder, cancellable, &local_error)) {
+			if (g_error_matches (local_error, EWS_CONNECTION_ERROR, EWS_CONNECTION_ERROR_ITEMNOTFOUND) ||
+			    g_error_matches (local_error, EWS_CONNECTION_ERROR, EWS_CONNECTION_ERROR_FOLDERNOTFOUND)) {
+				g_clear_error (&local_error);
+				local_error = g_error_new (
+					EWS_CONNECTION_ERROR, EWS_CONNECTION_ERROR_FOLDERNOTFOUND,
+					_("Folder '%s' not found. Either it does not exist or you do not have permission to access it."),
+					cffd->orig_foldername);
+			}
+
+			g_propagate_error (perror, local_error);
+			g_object_unref (conn);
+			return;
+		}
 	}
 
 	if (g_cancellable_set_error_if_cancelled (cancellable, perror)) {
@@ -518,6 +549,8 @@ subscribe_foreign_response_cb (GObject *
 		use_foldername = g_strdup ("contacts");
 	} else if (g_strcmp0 (orig_foldername, _("Calendar")) == 0) {
 		use_foldername = g_strdup ("calendar");
+	} else if (g_strcmp0 (orig_foldername, _("Free/Busy as Calendar")) == 0) {
+		use_foldername = g_strdup ("freebusy-calendar");
 	} else if (g_strcmp0 (orig_foldername, _("Memos")) == 0) {
 		use_foldername = g_strdup ("notes");
 	} else if (g_strcmp0 (orig_foldername, _("Tasks")) == 0) {
@@ -723,6 +756,7 @@ e_ews_subscribe_foreign_folder (GtkWindo
 	gtk_combo_box_text_append_text (combo_text, _("Inbox"));
 	gtk_combo_box_text_append_text (combo_text, _("Contacts"));
 	gtk_combo_box_text_append_text (combo_text, _("Calendar"));
+	gtk_combo_box_text_append_text (combo_text, _("Free/Busy as Calendar"));
 	gtk_combo_box_text_append_text (combo_text, _("Memos"));
 	gtk_combo_box_text_append_text (combo_text, _("Tasks"));
 	gtk_combo_box_set_active (GTK_COMBO_BOX (combo_text), 0);
diff -up evolution-ews-3.22.6/src/server/e-ews-calendar-utils.c.free-busy-calendar evolution-ews-3.22.6/src/server/e-ews-calendar-utils.c
--- evolution-ews-3.22.6/src/server/e-ews-calendar-utils.c.free-busy-calendar	2017-05-24 15:38:44.190519183 +0200
+++ evolution-ews-3.22.6/src/server/e-ews-calendar-utils.c	2017-05-24 15:38:44.190519183 +0200
@@ -0,0 +1,260 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+/*
+ * Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU Lesser General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
+ * USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "e-ews-message.h"
+
+#include "e-ews-calendar-utils.h"
+
+static const gchar *
+number_to_weekday (gint num)
+{
+	static const gchar *days[] = {
+		"Sunday", "Monday", "Tuesday", "Wednesday",
+		"Thursday", "Friday", "Saturday",
+		"Day", "Weekday", "WeekendDay"
+	};
+
+	return days[num - 1];
+}
+
+static void
+ewscal_add_availability_rrule (ESoapMessage *msg,
+                               icalproperty *prop)
+{
+	struct icalrecurrencetype recur = icalproperty_get_rrule (prop);
+	gchar buffer[16];
+	gint dayorder;
+
+	dayorder = icalrecurrencetype_day_position (recur.by_day[0]);
+	dayorder = dayorder % 5;
+	if (dayorder < 0)
+		dayorder += 5;
+	dayorder += 1;
+
+	/* expected value is 1..5, inclusive */
+	snprintf (buffer, 16, "%d", dayorder);
+	e_ews_message_write_string_parameter (msg, "DayOrder", NULL, buffer);
+
+	snprintf (buffer, 16, "%d", recur.by_month[0]);
+	e_ews_message_write_string_parameter (msg, "Month", NULL, buffer);
+
+	e_ews_message_write_string_parameter (msg, "DayOfWeek", NULL, number_to_weekday (icalrecurrencetype_day_day_of_week (recur.by_day[0])));
+}
+
+static void
+ewscal_add_availability_default_timechange (ESoapMessage *msg)
+{
+
+	e_soap_message_start_element (msg, "StandardTime", NULL, NULL);
+	e_ews_message_write_string_parameter (msg, "Bias", NULL, "0");
+	e_ews_message_write_string_parameter (msg, "Time", NULL, "00:00:00");
+	e_ews_message_write_string_parameter (msg, "DayOrder", NULL, "0");
+	e_ews_message_write_string_parameter (msg, "Month", NULL, "0");
+	e_ews_message_write_string_parameter (msg, "DayOfWeek", NULL, "Sunday");
+	e_soap_message_end_element (msg);
+
+	e_soap_message_start_element (msg, "DaylightTime", NULL, NULL);
+	e_ews_message_write_string_parameter (msg, "Bias", NULL, "0");
+	e_ews_message_write_string_parameter (msg, "Time", NULL, "00:00:00");
+	e_ews_message_write_string_parameter (msg, "DayOrder", NULL, "0");
+	e_ews_message_write_string_parameter (msg, "Month", NULL, "0");
+	e_ews_message_write_string_parameter (msg, "DayOfWeek", NULL, "Sunday");
+	e_soap_message_end_element (msg);
+}
+
+static void
+ewscal_add_availability_timechange (ESoapMessage *msg,
+                                    icalcomponent *comp,
+                                    gint baseoffs)
+{
+	gchar buffer[16];
+	icalproperty *prop;
+	struct icaltimetype dtstart;
+	gint utcoffs;
+
+	/* Calculate zone Offset from BaseOffset */
+	prop = icalcomponent_get_first_property (comp, ICAL_TZOFFSETTO_PROPERTY);
+	if (prop) {
+		utcoffs = -icalproperty_get_tzoffsetto (prop) / 60;
+		utcoffs -= baseoffs;
+		snprintf (buffer, 16, "%d", utcoffs);
+		e_ews_message_write_string_parameter (msg, "Bias", NULL, buffer);
+	}
+
+	prop = icalcomponent_get_first_property (comp, ICAL_DTSTART_PROPERTY);
+	if (prop) {
+		dtstart = icalproperty_get_dtstart (prop);
+		snprintf (buffer, 16, "%02d:%02d:%02d", dtstart.hour, dtstart.minute, dtstart.second);
+		e_ews_message_write_string_parameter (msg, "Time", NULL, buffer);
+	}
+
+	prop = icalcomponent_get_first_property (comp, ICAL_RRULE_PROPERTY);
+	if (prop)
+		ewscal_add_availability_rrule (msg, prop);
+}
+
+static void
+ewscal_set_availability_timezone (ESoapMessage *msg,
+                                  icaltimezone *icaltz)
+{
+	icalcomponent *comp;
+	icalproperty *prop;
+	icalcomponent *xstd, *xdaylight;
+	gint std_utcoffs;
+	gchar *offset;
+
+	if (!icaltz)
+		return;
+
+	comp = icaltimezone_get_component (icaltz);
+
+	xstd = icalcomponent_get_first_component (comp, ICAL_XSTANDARD_COMPONENT);
+	xdaylight = icalcomponent_get_first_component (comp, ICAL_XDAYLIGHT_COMPONENT);
+
+	/*TimeZone is the root element of GetUserAvailabilityRequest*/
+	e_soap_message_start_element (msg, "TimeZone", NULL, NULL);
+
+	/* Fetch the timezone offsets for the standard (or only) zone.
+	 * Negate it, because Exchange does it backwards */
+	if (xstd) {
+		prop = icalcomponent_get_first_property (xstd, ICAL_TZOFFSETTO_PROPERTY);
+		std_utcoffs = -icalproperty_get_tzoffsetto (prop) / 60;
+	} else
+		std_utcoffs = 0;
+
+	/* This is the overall BaseOffset tag, which the Standard and Daylight
+	 * zones are offset from. It's redundant, but Exchange always sets it
+	 * to the offset of the Standard zone, and the Offset in the Standard
+	 * zone to zero. So try to avoid problems by doing the same. */
+	offset = g_strdup_printf ("%d", std_utcoffs);
+	e_ews_message_write_string_parameter (msg, "Bias", NULL, offset);
+	g_free (offset);
+
+	if (xdaylight) {
+		/* Standard */
+		e_soap_message_start_element (msg, "StandardTime", NULL, NULL);
+		ewscal_add_availability_timechange (msg, xstd, std_utcoffs);
+		e_soap_message_end_element (msg); /* "StandardTime" */
+
+		/* DayLight */
+		e_soap_message_start_element (msg, "DaylightTime", NULL, NULL);
+		ewscal_add_availability_timechange (msg, xdaylight, std_utcoffs);
+		e_soap_message_end_element (msg); /* "DaylightTime" */
+	} else
+		/* Set default values*/
+		ewscal_add_availability_default_timechange (msg);
+
+	e_soap_message_end_element (msg); /* "TimeZone" */
+}
+
+void
+e_ews_cal_utils_prepare_free_busy_request (ESoapMessage *msg,
+					   gpointer user_data)
+{
+	const EEWSFreeBusyData *fbdata = user_data;
+	icaltimetype t_start, t_end;
+	icaltimezone *utc_zone = icaltimezone_get_utc_timezone ();
+	GSList *link;
+
+	g_return_if_fail (fbdata != NULL);
+
+	ewscal_set_availability_timezone (msg, utc_zone);
+
+	e_soap_message_start_element (msg, "MailboxDataArray", "messages", NULL);
+
+	for (link = (GSList *) fbdata->user_mails; link; link = g_slist_next (link)) {
+		const gchar *mail = link->data;
+
+		e_soap_message_start_element (msg, "MailboxData", NULL, NULL);
+
+		e_soap_message_start_element (msg, "Email", NULL, NULL);
+		e_ews_message_write_string_parameter (msg, "Address", NULL, mail);
+		e_soap_message_end_element (msg); /* "Email" */
+
+		e_ews_message_write_string_parameter (msg, "AttendeeType", NULL, "Required");
+		e_ews_message_write_string_parameter (msg, "ExcludeConflicts", NULL, "false");
+
+		e_soap_message_end_element (msg); /* "MailboxData" */
+	}
+
+	e_soap_message_end_element (msg); /* "MailboxDataArray" */
+
+	e_soap_message_start_element (msg, "FreeBusyViewOptions", NULL, NULL);
+
+	e_soap_message_start_element (msg, "TimeWindow", NULL, NULL);
+	t_start = icaltime_from_timet_with_zone (fbdata->period_start, 0, utc_zone);
+	t_end = icaltime_from_timet_with_zone (fbdata->period_end, 0, utc_zone);
+	e_ews_cal_utils_set_time (msg, "StartTime", &t_start, FALSE);
+	e_ews_cal_utils_set_time (msg, "EndTime", &t_end, FALSE);
+	e_soap_message_end_element (msg); /* "TimeWindow" */
+
+	e_ews_message_write_string_parameter (msg, "MergedFreeBusyIntervalInMinutes", NULL, "60");
+	e_ews_message_write_string_parameter (msg, "RequestedView", NULL, "DetailedMerged");
+
+	e_soap_message_end_element (msg); /* "FreeBusyViewOptions" */
+}
+
+void
+e_ews_cal_utils_set_time (ESoapMessage *msg,
+			  const gchar *name,
+			  icaltimetype *tt,
+			  gboolean with_timezone)
+{
+	gchar *str;
+	gchar *tz_ident = NULL;
+
+	g_return_if_fail (tt != NULL);
+
+	if (with_timezone) {
+		if (tt->is_utc || !tt->zone || tt->zone == icaltimezone_get_utc_timezone ()) {
+			tz_ident = g_strdup ("Z");
+		} else {
+			gint offset, is_daylight, hrs, mins;
+
+			offset = icaltimezone_get_utc_offset (
+				icaltimezone_get_utc_timezone (), tt, &is_daylight);
+
+			offset = offset * (-1);
+			hrs = offset / 60;
+			mins = offset % 60;
+
+			if (hrs < 0)
+				hrs *= -1;
+			if (mins < 0)
+				mins *= -1;
+
+			tz_ident = g_strdup_printf ("%s%02d:%02d", offset > 0 ? "+" : "-", hrs, mins);
+		}
+	}
+
+	str = g_strdup_printf (
+		"%04d-%02d-%02dT%02d:%02d:%02d%s",
+		tt->year, tt->month, tt->day,
+		tt->hour, tt->minute, tt->second,
+		tz_ident ? tz_ident : "");
+
+	e_ews_message_write_string_parameter (msg, name, NULL, str);
+
+	g_free (tz_ident);
+	g_free (str);
+}
diff -up evolution-ews-3.22.6/src/server/e-ews-calendar-utils.h.free-busy-calendar evolution-ews-3.22.6/src/server/e-ews-calendar-utils.h
--- evolution-ews-3.22.6/src/server/e-ews-calendar-utils.h.free-busy-calendar	2017-05-24 15:38:44.190519183 +0200
+++ evolution-ews-3.22.6/src/server/e-ews-calendar-utils.h	2017-05-24 15:38:44.190519183 +0200
@@ -0,0 +1,46 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+/*
+ * Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU Lesser General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
+ * USA
+ */
+
+#ifndef E_EWS_CALENDAR_UTILS_H
+#define E_EWS_CALENDAR_UTILS_H
+
+#include <time.h>
+#include <libical/ical.h>
+
+#include "server/e-soap-message.h"
+
+G_BEGIN_DECLS
+
+typedef struct _EEWSFreeBusyData {
+	time_t period_start;
+	time_t period_end;
+	GSList *user_mails; /* gchar * */
+} EEWSFreeBusyData;
+
+void		e_ews_cal_utils_prepare_free_busy_request
+						(ESoapMessage *msg,
+						 gpointer user_data); /* EEWSFreeBusyData * */
+void		e_ews_cal_utils_set_time	(ESoapMessage *msg,
+						 const gchar *name,
+						 icaltimetype *tt,
+						 gboolean with_timezone);
+
+G_END_DECLS
+
+#endif /* E_EWS_CALENDAR_UTILS_H */
diff -up evolution-ews-3.22.6/src/server/e-ews-connection.c.free-busy-calendar evolution-ews-3.22.6/src/server/e-ews-connection.c
--- evolution-ews-3.22.6/src/server/e-ews-connection.c.free-busy-calendar	2017-05-24 15:38:44.183519217 +0200
+++ evolution-ews-3.22.6/src/server/e-ews-connection.c	2017-05-24 15:38:44.191519178 +0200
@@ -7316,13 +7316,15 @@ ews_handle_free_busy_view (ESoapParamete
 	ESoapParameter *viewparam, *eventarray, *event_param, *subparam;
 	GTimeVal t_val;
 	const gchar *name;
-	gchar *value, *new_val = NULL, *summary = NULL, *location = NULL;
+	gchar *value, *new_val = NULL, *summary = NULL, *location = NULL, *id = NULL;
 
 	viewparam = e_soap_parameter_get_first_child_by_name (param, "FreeBusyView");
 	if (!viewparam) return;
 	vfb = icalcomponent_new_vfreebusy ();
 	eventarray = e_soap_parameter_get_first_child_by_name (viewparam, "CalendarEventArray");
-	for (event_param = e_soap_parameter_get_first_child (eventarray); event_param != NULL; event_param = e_soap_parameter_get_next_child (event_param), icalprop = NULL) {
+	for (event_param = eventarray ? e_soap_parameter_get_first_child (eventarray) : NULL;
+	     event_param != NULL;
+	     event_param = e_soap_parameter_get_next_child (event_param), icalprop = NULL) {
 		for (subparam = e_soap_parameter_get_first_child (event_param); subparam != NULL; subparam = e_soap_parameter_get_next_child (subparam)) {
 			name = e_soap_parameter_get_name (subparam);
 
@@ -7379,6 +7381,10 @@ ews_handle_free_busy_view (ESoapParamete
 			} else if (!g_ascii_strcasecmp (name, "CalendarEventDetails")) {
 				ESoapParameter *dparam;
 
+				dparam = e_soap_parameter_get_first_child_by_name (subparam, "ID");
+				if (dparam)
+					id = e_soap_parameter_get_string_value (dparam);
+
 				dparam = e_soap_parameter_get_first_child_by_name (subparam, "Subject");
 				if (dparam)
 					summary = e_soap_parameter_get_string_value (dparam);
@@ -7389,6 +7395,8 @@ ews_handle_free_busy_view (ESoapParamete
 			}
 		}
 		if (icalprop != NULL) {
+			if (id)
+				icalproperty_set_parameter_from_string (icalprop, "X-EWS-ID", id);
 			if (summary)
 				icalproperty_set_parameter_from_string (icalprop, "X-SUMMARY", summary);
 			if (location)
@@ -7396,10 +7404,9 @@ ews_handle_free_busy_view (ESoapParamete
 			icalcomponent_add_property (vfb, icalprop);
 		}
 
-		g_free (summary);
-		g_free (location);
-		summary = NULL;
-		location = NULL;
+		g_clear_pointer (&summary, g_free);
+		g_clear_pointer (&location, g_free);
+		g_clear_pointer (&id, g_free);
 	}
 
 	async_data->items = g_slist_append (async_data->items, vfb);
diff -up evolution-ews-3.22.6/src/server/e-ews-folder.c.free-busy-calendar evolution-ews-3.22.6/src/server/e-ews-folder.c
--- evolution-ews-3.22.6/src/server/e-ews-folder.c.free-busy-calendar	2015-05-22 13:47:17.000000000 +0200
+++ evolution-ews-3.22.6/src/server/e-ews-folder.c	2017-05-24 15:38:44.192519174 +0200
@@ -47,6 +47,7 @@ struct _EEwsFolderPrivate {
 	guint32 child_count;
 	guint64 size;
 	gboolean foreign;
+	gchar *foreign_mail;
 };
 
 static void
@@ -70,14 +71,9 @@ e_ews_folder_finalize (GObject *object)
 	priv = folder->priv;
 
 	g_clear_error (&priv->error);
-
-	if (priv->name) {
-		g_free (priv->name);
-		priv->name = NULL;
-	}
-
-	g_free (priv->escaped_name);
-	priv->escaped_name = NULL;
+	g_clear_pointer (&priv->name, g_free);
+	g_clear_pointer (&priv->escaped_name, g_free);
+	g_clear_pointer (&priv->foreign_mail, g_free);
 
 	if (priv->fid) {
 		g_free (priv->fid->id);
@@ -409,6 +405,16 @@ e_ews_folder_get_id (const EEwsFolder *f
 	return (const EwsFolderId *) folder->priv->fid;
 }
 
+void
+e_ews_folder_set_id (EEwsFolder *folder,
+		     EwsFolderId *fid)
+{
+	g_return_if_fail (E_IS_EWS_FOLDER (folder));
+
+	e_ews_folder_id_free (folder->priv->fid);
+	folder->priv->fid = fid;
+}
+
 const EwsFolderId *
 e_ews_folder_get_parent_id (const EEwsFolder *folder)
 {
@@ -503,6 +509,24 @@ e_ews_folder_set_foreign (EEwsFolder *fo
 	folder->priv->foreign = is_foreign;
 }
 
+const gchar *
+e_ews_folder_get_foreign_mail (const EEwsFolder *folder)
+{
+	g_return_val_if_fail (E_IS_EWS_FOLDER (folder), NULL);
+
+	return folder->priv->foreign_mail;
+}
+
+void
+e_ews_folder_set_foreign_mail (EEwsFolder *folder,
+			       const gchar *foreign_mail)
+{
+	g_return_if_fail (E_IS_EWS_FOLDER (folder));
+
+	g_free (folder->priv->foreign_mail);
+	folder->priv->foreign_mail = g_strdup (foreign_mail);
+}
+
 /* escapes backslashes with \5C and forward slashes with \2F */
 gchar *
 e_ews_folder_utils_escape_name (const gchar *folder_name)
@@ -678,6 +702,7 @@ e_ews_folder_utils_populate_esource (ESo
 			e_source_ews_folder_set_change_key (folder_ext, NULL);
 			e_source_ews_folder_set_foreign (folder_ext, e_ews_folder_get_foreign (folder));
 			e_source_ews_folder_set_foreign_subfolders (folder_ext, (flags & E_EWS_ESOURCE_FLAG_INCLUDE_SUBFOLDERS) != 0);
+			e_source_ews_folder_set_foreign_mail (folder_ext, e_ews_folder_get_foreign_mail (folder));
 			e_source_ews_folder_set_public (folder_ext, (flags & E_EWS_ESOURCE_FLAG_PUBLIC_FOLDER) != 0);
 
 			offline_ext = e_source_get_extension (source, E_SOURCE_EXTENSION_OFFLINE);
diff -up evolution-ews-3.22.6/src/server/e-ews-folder.h.free-busy-calendar evolution-ews-3.22.6/src/server/e-ews-folder.h
--- evolution-ews-3.22.6/src/server/e-ews-folder.h.free-busy-calendar	2014-11-19 19:06:36.000000000 +0100
+++ evolution-ews-3.22.6/src/server/e-ews-folder.h	2017-05-24 15:38:44.192519174 +0200
@@ -69,6 +69,7 @@ const EwsFolderId *
 		e_ews_folder_get_parent_id (const EEwsFolder *folder);
 const EwsFolderId *
 		e_ews_folder_get_id (const EEwsFolder *folder);
+void		e_ews_folder_set_id (EEwsFolder *folder, EwsFolderId *fid);
 guint32		e_ews_folder_get_total_count (const EEwsFolder *folder);
 guint32		e_ews_folder_get_unread_count (const EEwsFolder *folder);
 guint32		e_ews_folder_get_child_count (const EEwsFolder *folder);
@@ -79,6 +80,8 @@ EEwsFolderType	e_ews_folder_get_folder_t
 void		e_ews_folder_set_folder_type (EEwsFolder *folder, EEwsFolderType folder_type);
 gboolean	e_ews_folder_get_foreign (const EEwsFolder *folder);
 void		e_ews_folder_set_foreign (EEwsFolder *folder, gboolean is_foreign);
+const gchar *	e_ews_folder_get_foreign_mail (const EEwsFolder *folder);
+void		e_ews_folder_set_foreign_mail (EEwsFolder *folder, const gchar *foreign_mail);
 
 EwsFolderId *	e_ews_folder_id_new (const gchar *id,
 				     const gchar *change_key,
diff -up evolution-ews-3.22.6/src/server/e-source-ews-folder.c.free-busy-calendar evolution-ews-3.22.6/src/server/e-source-ews-folder.c
--- evolution-ews-3.22.6/src/server/e-source-ews-folder.c.free-busy-calendar	2015-09-21 11:59:31.000000000 +0200
+++ evolution-ews-3.22.6/src/server/e-source-ews-folder.c	2017-05-24 15:38:44.192519174 +0200
@@ -31,7 +31,10 @@ struct _ESourceEwsFolderPrivate {
 	gchar *id;
 	gboolean foreign;
 	gboolean foreign_subfolders;
+	gchar *foreign_mail;
 	gboolean is_public;
+	guint freebusy_weeks_before;
+	guint freebusy_weeks_after;
 };
 
 enum {
@@ -40,6 +43,9 @@ enum {
 	PROP_ID,
 	PROP_FOREIGN,
 	PROP_FOREIGN_SUBFOLDERS,
+	PROP_FOREIGN_MAIL,
+	PROP_FREEBUSY_WEEKS_BEFORE,
+	PROP_FREEBUSY_WEEKS_AFTER,
 	PROP_PUBLIC
 };
 
@@ -79,6 +85,24 @@ source_ews_folder_set_property (GObject
 				g_value_get_boolean (value));
 			return;
 
+		case PROP_FOREIGN_MAIL:
+			e_source_ews_folder_set_foreign_mail (
+				E_SOURCE_EWS_FOLDER (object),
+				g_value_get_string (value));
+			return;
+
+		case PROP_FREEBUSY_WEEKS_BEFORE:
+			e_source_ews_folder_set_freebusy_weeks_before (
+				E_SOURCE_EWS_FOLDER (object),
+				g_value_get_uint (value));
+			return;
+
+		case PROP_FREEBUSY_WEEKS_AFTER:
+			e_source_ews_folder_set_freebusy_weeks_after (
+				E_SOURCE_EWS_FOLDER (object),
+				g_value_get_uint (value));
+			return;
+
 		case PROP_PUBLIC:
 			e_source_ews_folder_set_public (
 				E_SOURCE_EWS_FOLDER (object),
@@ -124,6 +148,27 @@ source_ews_folder_get_property (GObject
 				E_SOURCE_EWS_FOLDER (object)));
 			return;
 
+		case PROP_FOREIGN_MAIL:
+			g_value_take_string (
+				value,
+				e_source_ews_folder_dup_foreign_mail (
+				E_SOURCE_EWS_FOLDER (object)));
+			return;
+
+		case PROP_FREEBUSY_WEEKS_BEFORE:
+			g_value_set_uint (
+				value,
+				e_source_ews_folder_get_freebusy_weeks_before (
+				E_SOURCE_EWS_FOLDER (object)));
+			return;
+
+		case PROP_FREEBUSY_WEEKS_AFTER:
+			g_value_set_uint (
+				value,
+				e_source_ews_folder_get_freebusy_weeks_after (
+				E_SOURCE_EWS_FOLDER (object)));
+			return;
+
 		case PROP_PUBLIC:
 			g_value_set_boolean (
 				value,
@@ -144,6 +189,7 @@ source_ews_folder_finalize (GObject *obj
 
 	g_free (priv->change_key);
 	g_free (priv->id);
+	g_free (priv->foreign_mail);
 
 	/* Chain up to parent's finalize() method. */
 	G_OBJECT_CLASS (e_source_ews_folder_parent_class)->finalize (object);
@@ -220,6 +266,45 @@ e_source_ews_folder_class_init (ESourceE
 
 	g_object_class_install_property (
 		object_class,
+		PROP_FOREIGN_MAIL,
+		g_param_spec_string (
+			"foreign-mail",
+			"ForeignMail",
+			"Other user's mail address",
+			NULL,
+			G_PARAM_READWRITE |
+			G_PARAM_CONSTRUCT |
+			G_PARAM_STATIC_STRINGS |
+			E_SOURCE_PARAM_SETTING));
+
+	g_object_class_install_property (
+		object_class,
+		PROP_FREEBUSY_WEEKS_BEFORE,
+		g_param_spec_uint (
+			"freebusy-weeks-before",
+			"FreeBusyWeeksBefore",
+			"How many weeks to read Free/Busy before today",
+			0, 5, 1,
+			G_PARAM_READWRITE |
+			G_PARAM_CONSTRUCT |
+			G_PARAM_STATIC_STRINGS |
+			E_SOURCE_PARAM_SETTING));
+
+	g_object_class_install_property (
+		object_class,
+		PROP_FREEBUSY_WEEKS_AFTER,
+		g_param_spec_uint (
+			"freebusy-weeks-after",
+			"FreeBusyWeeksAfter",
+			"How many weeks to read Free/Busy after today",
+			1, 54, 5,
+			G_PARAM_READWRITE |
+			G_PARAM_CONSTRUCT |
+			G_PARAM_STATIC_STRINGS |
+			E_SOURCE_PARAM_SETTING));
+
+	g_object_class_install_property (
+		object_class,
 		PROP_PUBLIC,
 		g_param_spec_boolean (
 			"public",
@@ -402,6 +487,97 @@ e_source_ews_folder_set_foreign_subfolde
 	g_object_notify (G_OBJECT (extension), "foreign-subfolders");
 }
 
+const gchar *
+e_source_ews_folder_get_foreign_mail (ESourceEwsFolder *extension)
+{
+	g_return_val_if_fail (E_IS_SOURCE_EWS_FOLDER (extension), NULL);
+
+	return extension->priv->foreign_mail;
+}
+
+gchar *
+e_source_ews_folder_dup_foreign_mail (ESourceEwsFolder *extension)
+{
+	const gchar *protected;
+	gchar *duplicate;
+
+	g_return_val_if_fail (E_IS_SOURCE_EWS_FOLDER (extension), NULL);
+
+	e_source_extension_property_lock (E_SOURCE_EXTENSION (extension));
+
+	protected = e_source_ews_folder_get_foreign_mail (extension);
+	duplicate = g_strdup (protected);
+
+	e_source_extension_property_unlock (E_SOURCE_EXTENSION (extension));
+
+	return duplicate;
+}
+
+void
+e_source_ews_folder_set_foreign_mail (ESourceEwsFolder *extension,
+				      const gchar *foreign_mail)
+{
+	g_return_if_fail (E_IS_SOURCE_EWS_FOLDER (extension));
+
+	e_source_extension_property_lock (E_SOURCE_EXTENSION (extension));
+
+	if (g_strcmp0 (extension->priv->foreign_mail, foreign_mail) == 0) {
+		e_source_extension_property_unlock (E_SOURCE_EXTENSION (extension));
+		return;
+	}
+
+	g_free (extension->priv->foreign_mail);
+	extension->priv->foreign_mail = g_strdup (foreign_mail);
+
+	e_source_extension_property_unlock (E_SOURCE_EXTENSION (extension));
+
+	g_object_notify (G_OBJECT (extension), "foreign-mail");
+}
+
+guint
+e_source_ews_folder_get_freebusy_weeks_before (ESourceEwsFolder *extension)
+{
+	g_return_val_if_fail (E_IS_SOURCE_EWS_FOLDER (extension), 0);
+
+	return extension->priv->freebusy_weeks_before;
+}
+
+void
+e_source_ews_folder_set_freebusy_weeks_before (ESourceEwsFolder *extension,
+					       guint freebusy_weeks_before)
+{
+	g_return_if_fail (E_IS_SOURCE_EWS_FOLDER (extension));
+
+	if (extension->priv->freebusy_weeks_before == freebusy_weeks_before)
+		return;
+
+	extension->priv->freebusy_weeks_before = freebusy_weeks_before;
+
+	g_object_notify (G_OBJECT (extension), "freebusy-weeks-before");
+}
+
+guint
+e_source_ews_folder_get_freebusy_weeks_after (ESourceEwsFolder *extension)
+{
+	g_return_val_if_fail (E_IS_SOURCE_EWS_FOLDER (extension), 0);
+
+	return extension->priv->freebusy_weeks_after;
+}
+
+void
+e_source_ews_folder_set_freebusy_weeks_after (ESourceEwsFolder *extension,
+					      guint freebusy_weeks_after)
+{
+	g_return_if_fail (E_IS_SOURCE_EWS_FOLDER (extension));
+
+	if (extension->priv->freebusy_weeks_after == freebusy_weeks_after)
+		return;
+
+	extension->priv->freebusy_weeks_after = freebusy_weeks_after;
+
+	g_object_notify (G_OBJECT (extension), "freebusy-weeks-after");
+}
+
 gboolean
 e_source_ews_folder_get_public (ESourceEwsFolder *extension)
 {
diff -up evolution-ews-3.22.6/src/server/e-source-ews-folder.h.free-busy-calendar evolution-ews-3.22.6/src/server/e-source-ews-folder.h
--- evolution-ews-3.22.6/src/server/e-source-ews-folder.h.free-busy-calendar	2014-03-24 10:28:36.000000000 +0100
+++ evolution-ews-3.22.6/src/server/e-source-ews-folder.h	2017-05-24 15:38:44.192519174 +0200
@@ -84,6 +84,23 @@ gboolean	e_source_ews_folder_get_foreign
 void		e_source_ews_folder_set_foreign_subfolders
 						(ESourceEwsFolder *extension,
 						 gboolean foreign_subfolders);
+const gchar *	e_source_ews_folder_get_foreign_mail
+						(ESourceEwsFolder *extension);
+gchar *		e_source_ews_folder_dup_foreign_mail
+						(ESourceEwsFolder *extension);
+void		e_source_ews_folder_set_foreign_mail
+						(ESourceEwsFolder *extension,
+						 const gchar *foreign_mail);
+guint		e_source_ews_folder_get_freebusy_weeks_before
+						(ESourceEwsFolder *extension);
+void		e_source_ews_folder_set_freebusy_weeks_before
+						(ESourceEwsFolder *extension,
+						 guint freebusy_weeks_before);
+guint		e_source_ews_folder_get_freebusy_weeks_after
+						(ESourceEwsFolder *extension);
+void		e_source_ews_folder_set_freebusy_weeks_after
+						(ESourceEwsFolder *extension,
+						 guint freebusy_weeks_after);
 gboolean	e_source_ews_folder_get_public	(ESourceEwsFolder *extension);
 void		e_source_ews_folder_set_public	(ESourceEwsFolder *extension,
 						 gboolean is_public);
diff -up evolution-ews-3.22.6/src/server/Makefile.am.free-busy-calendar evolution-ews-3.22.6/src/server/Makefile.am
--- evolution-ews-3.22.6/src/server/Makefile.am.free-busy-calendar	2016-09-26 23:54:19.000000000 +0200
+++ evolution-ews-3.22.6/src/server/Makefile.am	2017-05-24 15:38:44.190519183 +0200
@@ -41,6 +41,8 @@ libeews_1_2_la_SOURCES = \
 	camel-ews-settings.c \
 	ews-errors.h \
 	ews-errors.c \
+	e-ews-calendar-utils.c \
+	e-ews-calendar-utils.h \
 	e-ews-connection.c \
 	e-ews-connection.h \
 	e-ews-connection-utils.c \