diff --git a/libbalsa/rfc2445.c b/libbalsa/rfc2445.c
index 98d5108e6..6bb2f6a98 100644
--- a/libbalsa/rfc2445.c
+++ b/libbalsa/rfc2445.c
@@ -501,13 +501,6 @@ libbalsa_vcal_vevent(LibBalsaVCal *vcal, guint nth_event)
  * features als Thunderbird's "Lightning" extension, which should be fine for the majority of cases in the wild.  However, there
  * /may/ (and will) be cases where these function just fail... */
 
-static inline gboolean
-ical_ar_empty(const short *array)
-{
-	return array[0] == ICAL_RECURRENCE_ARRAY_MAX;
-}
-
-
 static inline const gchar *
 day_name(gint day)
 {
@@ -537,8 +530,8 @@ ical_check_bydays(const struct icalrecurrencetype *rrule, guint want_days)
 	guint have_days = 0U;
 	guint n;
 
-	for (n = 0U; (n < ICAL_BY_DAY_SIZE) && (rrule->by_day[n] != ICAL_RECURRENCE_ARRAY_MAX); n++) {
-		have_days |= (1U << rrule->by_day[n]);
+	for (n = 0U; n < rrule->by[ICAL_BY_DAY].size; n++) {
+		have_days |= (1U << rrule->by[ICAL_BY_DAY].data[n]);
 	}
 	return want_days == have_days;
 }
@@ -566,7 +559,8 @@ vevent_recurrence_weekly(const struct icalrecurrencetype *rrule)
 {
 	GString *result = g_string_new(NULL);
 
-	if (!ical_ar_empty(rrule->by_day)) {
+	size_t by_day_size = rrule->by[ICAL_BY_DAY].size;
+	if (by_day_size > 0) {
 		gint n;
 
 		if (rrule->interval == 1) {
@@ -575,13 +569,13 @@ vevent_recurrence_weekly(const struct icalrecurrencetype *rrule)
 			/* #1: interval */
 			g_string_append_printf(result, _("every %d weeks on "), rrule->interval);
 		}
-		g_string_append(result, day_name(rrule->by_day[0] - 1));
-		for (n = 1; (n < ICAL_BY_DAY_SIZE) && (rrule->by_day[n] != ICAL_RECURRENCE_ARRAY_MAX); n++) {
-			if ((n < (ICAL_BY_DAY_SIZE - 1)) && (rrule->by_day[n + 1] != ICAL_RECURRENCE_ARRAY_MAX)) {
-				g_string_append_printf(result, ", %s", day_name(rrule->by_day[n] - 1));
+		g_string_append(result, day_name(rrule->by[ICAL_BY_DAY].data[0] - 1));
+		for (n = 1; n < (gint)by_day_size; n++) {
+			if (n < (gint)by_day_size - 1) {
+				g_string_append_printf(result, ", %s", day_name(rrule->by[ICAL_BY_DAY].data[n] - 1));
 			} else {
 				/* #1: the day of week (defined in the day_of_week context) */
-				g_string_append_printf(result, _(" and %s"), day_name(rrule->by_day[n] - 1));
+				g_string_append_printf(result, _(" and %s"), day_name(rrule->by[ICAL_BY_DAY].data[n] - 1));
 			}
 		}
 	} else {
@@ -634,7 +628,7 @@ vevent_recurrence_monthly(const struct icalrecurrencetype *rrule, const icaltime
 {
 	GString *result = g_string_new(NULL);
 
-	if (!ical_ar_empty(rrule->by_day)) {
+	if (rrule->by[ICAL_BY_DAY].size > 0) {
 		/* we have a "BYDAY" rule */
 		if (ical_check_bydays(rrule, 0xfeU)) {
 			if (rrule->interval == 1) {
@@ -649,18 +643,19 @@ vevent_recurrence_monthly(const struct icalrecurrencetype *rrule, const icaltime
 			guint every_mask = 0U;
 			GList *days = NULL;
 			GList *p;
+			size_t by_day_size = rrule->by[ICAL_BY_DAY].size;
 
 			/* collect all days repeating every week */
-			for (n = 0U; (n < ICAL_BY_DAY_SIZE) && (rrule->by_day[n] != ICAL_RECURRENCE_ARRAY_MAX); n++) {
+			for (n = 0U; n < by_day_size; n++) {
 				int day_pos;
 
-				day_pos = icalrecurrencetype_day_position(rrule->by_day[n]);
+				day_pos = icalrecurrencetype_day_position(rrule->by[ICAL_BY_DAY].data[n]);
 				if ((day_pos < -1) || (day_pos > 5)) {
 					return g_string_assign(result, _("rule too complex"));
 				} else if (day_pos == 0) {
 					int day_of_week;
 
-					day_of_week = icalrecurrencetype_day_day_of_week(rrule->by_day[n]);
+					day_of_week = icalrecurrencetype_day_day_of_week(rrule->by[ICAL_BY_DAY].data[n]);
 					every_mask |= 1U << day_of_week;
 					/* #1: the day of week (defined in the day_of_week context) */
 					days = g_list_append(days, g_strdup_printf(_("every %s"), day_name(day_of_week - 1)));
@@ -670,15 +665,15 @@ vevent_recurrence_monthly(const struct icalrecurrencetype *rrule, const icaltime
 			}
 
 			/* collect specific ones, but avoid something like "Monday and the last Monday" */
-			for (n = 0U; (n < ICAL_BY_DAY_SIZE) && (rrule->by_day[n] != ICAL_RECURRENCE_ARRAY_MAX); n++) {
+			for (n = 0U; n < by_day_size; n++) {
 				int day_of_week;
 
-				day_of_week = icalrecurrencetype_day_day_of_week(rrule->by_day[n]);
+				day_of_week = icalrecurrencetype_day_day_of_week(rrule->by[ICAL_BY_DAY].data[n]);
 				if ((every_mask & (1U << day_of_week)) == 0U) {
 					int day_pos;
 					GString *buffer = g_string_new(NULL);
 
-					day_pos = icalrecurrencetype_day_position(rrule->by_day[n]);
+					day_pos = icalrecurrencetype_day_position(rrule->by[ICAL_BY_DAY].data[n]);
 					day_ordinal_append(buffer, day_pos, day_name(day_of_week - 1), day_name(day_of_week - 1));
 					days = g_list_append(days, g_string_free(buffer, FALSE));
 				}
@@ -696,22 +691,23 @@ vevent_recurrence_monthly(const struct icalrecurrencetype *rrule, const icaltime
 			}
 			g_list_free_full(days, g_free);
 		}
-	} else if (!ical_ar_empty(rrule->by_month_day)) {
+	} else if (rrule->by[ICAL_BY_MONTH_DAY].size > 0) {
 		/* we have a "BYMONTHDAY" rule */
 		guint n;
 
-		for (n = 0; (n < ICAL_BY_MONTHDAY_SIZE) && (rrule->by_month_day[n] != ICAL_RECURRENCE_ARRAY_MAX); n++) {
-			if (rrule->by_month_day[n] < -1) {
+		size_t by_month_day_size = rrule->by[ICAL_BY_MONTH_DAY].size;
+		for (n = 0; n < by_month_day_size; n++) {
+			if (rrule->by[ICAL_BY_MONTH_DAY].data[n] < -1) {
 				return g_string_assign(result, _("rule too complex"));
 			} else {
 				if (n > 0) {
-					if (rrule->by_month_day[n + 1] != ICAL_RECURRENCE_ARRAY_MAX) {
+					if (n + 1 < by_month_day_size) {
 						g_string_append(result, ", ");
 					} else {
 						g_string_append(result, _(" and "));
 					}
 				}
-				day_ordinal_append(result, rrule->by_month_day[n], _("day"), NULL);
+				day_ordinal_append(result, rrule->by[ICAL_BY_MONTH_DAY].data[n], _("day"), NULL);
 			}
 		}
 	} else {
@@ -749,12 +745,12 @@ vevent_recurrence_yearly(const struct icalrecurrencetype *rrule, const icaltimet
 	GString *result = g_string_new(NULL);
 
 	/* rules which are too complex for Lightning, so ignore them here, too... */
-	if ((rrule->by_month[1] != ICAL_RECURRENCE_ARRAY_MAX) || (rrule->by_month_day[1] != ICAL_RECURRENCE_ARRAY_MAX) ||
-		(rrule->by_month_day[0] < -1)) {
+	if ((rrule->by[ICAL_BY_MONTH].size > 1) || (rrule->by[ICAL_BY_MONTH_DAY].size > 1) ||
+		(rrule->by[ICAL_BY_MONTH_DAY].size > 0 && rrule->by[ICAL_BY_MONTH_DAY].data[0] < -1)) {
 		return g_string_assign(result, _("rule too complex"));
 	}
 
-	if (ical_ar_empty(rrule->by_day)) {
+	if (rrule->by[ICAL_BY_DAY].size == 0) {
         /* RRULE:FREQ=YEARLY;BYMONTH=x;BYMONTHDAY=y.
          * RRULE:FREQ=YEARLY;BYMONTHDAY=x (takes the month from the start date)
          * RRULE:FREQ=YEARLY;BYMONTH=x (takes the day from the start date)
@@ -762,15 +758,15 @@ vevent_recurrence_yearly(const struct icalrecurrencetype *rrule, const icaltimet
 		const gchar *month;
 		GString *day = g_string_new(NULL);
 
-		if (ical_ar_empty(rrule->by_month)) {
+		if (rrule->by[ICAL_BY_MONTH].size == 0) {
 			month = mon_name[start->month - 1];
 		} else {
-			month = mon_name[rrule->by_month[0] - 1];
+			month = mon_name[rrule->by[ICAL_BY_MONTH].data[0] - 1];
 		}
-		if (ical_ar_empty(rrule->by_month_day)) {
+		if (rrule->by[ICAL_BY_MONTH_DAY].size == 0) {
 			day_ordinal_append(day, start->day, NULL, NULL);
 		} else {
-			day_ordinal_append(day, rrule->by_month_day[0], _("day"), NULL);
+			day_ordinal_append(day, rrule->by[ICAL_BY_MONTH_DAY].data[0], _("day"), NULL);
 		}
 		if (rrule->interval == 1) {
 			/* #1: name of month (defined in the name_of_month context) */
@@ -783,9 +779,9 @@ vevent_recurrence_yearly(const struct icalrecurrencetype *rrule, const icaltimet
 			g_string_append_printf(result, _("every %d years on %s %s"), rrule->interval, month, day->str);
 		}
 		g_string_free(day, TRUE);
-	} else if (!ical_ar_empty(rrule->by_month) && !ical_ar_empty(rrule->by_day)) {
+	} else if (rrule->by[ICAL_BY_MONTH].size > 0 && rrule->by[ICAL_BY_DAY].size > 0) {
 		/* RRULE:FREQ=YEARLY;BYMONTH=x;BYDAY=y1,y2,... */
-		const gchar *month = mon_name[rrule->by_month[0] - 1];
+		const gchar *month = mon_name[rrule->by[ICAL_BY_MONTH].data[0] - 1];
 
 		if (ical_check_bydays(rrule, 0x7cU)) {
 			/* every day of the month */
@@ -797,12 +793,12 @@ vevent_recurrence_yearly(const struct icalrecurrencetype *rrule, const icaltimet
 				/* #2: name of month (defined in the name_of_month context) */
 				g_string_append_printf(result, _("every %d years every day of %s"), rrule->interval, month);
 			}
-		} else if (rrule->by_day[1] == ICAL_RECURRENCE_ARRAY_MAX) {
+		} else if (rrule->by[ICAL_BY_DAY].size == 1) {
 			int day_pos;
 			int day_of_week;
 
-			day_pos = icalrecurrencetype_day_position(rrule->by_day[0]);
-			day_of_week = icalrecurrencetype_day_day_of_week(rrule->by_day[0]);
+			day_pos = icalrecurrencetype_day_position(rrule->by[ICAL_BY_DAY].data[0]);
+			day_of_week = icalrecurrencetype_day_day_of_week(rrule->by[ICAL_BY_DAY].data[0]);
 			if (day_pos == 0) {
 				if (rrule->interval == 1) {
 					/* #1: day of week (defined in the day_of_week context) */
@@ -1055,7 +1051,7 @@ vcalendar_extract(const gchar *vcal_buf)
 			/* RRULE (only one is allowed, see RFC 5546, Sect. 3.2.2) */
 			prop = icalcomponent_get_first_property(item, ICAL_RRULE_PROPERTY);
 			if (prop != NULL) {
-				event->rrule = icalproperty_get_rrule(prop);
+				event->rrule = *icalproperty_get_rrule(prop);
 			}
 
 			/* UID, SUMMARY, LOCATION, DESCRIPTION */