public function send_non_attendance_confirmation_legacy( $order_id, $event_id ) {

		$attendees = $this->get_attendees_by_order_id( $order_id );

		if ( empty( $attendees ) ) {
			return;
		}

		// For now all ticket holders in an order share the same email.
		$to = $attendees['0']['holder_email'];

		if ( ! is_email( $to ) ) {
			return;
		}

		/**
		 * Filters the non attending RSVP tickets email headers
		 *
		 * @since 4.5.2 added new parameters $event_id and $order_id
		 * @since 4.5.5 changed filter name to be unique to non attendance emails
		 *
		 * @param array  email headers
		 * @param int    $event_id
		 * @param int    $order_id
		 */
		$headers = apply_filters( 'tribe_rsvp_non_attendance_email_headers', [ 'Content-type: text/html' ], $event_id, $order_id );

		/**
		 * Filters the non attending RSVP tickets email attachments
		 *
		 * @since 4.5.2 added new parameters $event_id and $order_id
		 * @since 4.5.5 changed filter name to be unique to non attendance emails
		 *
		 * @param array  attachments
		 * @param int    $event_id
		 * @param int    $order_id
		 */
		$attachments = apply_filters( 'tribe_rsvp_non_attendance_email_attachments', [], $event_id, $order_id );

		/**
		 * Filters the non attending RSVP tickets email recipient.
		 *
		 * @since 4.5.2 added new parameters $event_id and $order_id
		 * @since 4.5.5 changed filter name to be unique to non attendance emails
		 *
		 * @param string  $to
		 * @param int     $event_id
		 * @param int     $order_id
		 */
		$to = apply_filters( 'tribe_rsvp_non_attendance_email_recipient', $to, $event_id, $order_id );

		/**
		 * Filters the non attending RSVP tickets email subject
		 *
		 * @since 4.5.2 added new parameters $event_id and $order_id
		 * @since 4.5.5 changed filter name to be unique to non attendance emails
		 *
		 * @param string
		 * @param int     $event_id
		 * @param int     $order_id
		 */
		$subject = apply_filters(
			'tribe_rsvp_non_attendance_email_subject',
			sprintf(
				// Translators: %s: Event name.
				__( 'You confirmed you will not be attending %s', 'event-tickets' ),
				get_the_title( $event_id )
			),
			$event_id,
			$order_id
		);

		$template_data = [
			'event_id'  => $event_id,
			'order_id'  => $order_id,
			'attendees' => $attendees,
		];

		/**
		 * Filters the non attending RSVP tickets email content
		 *
		 * @since 4.5.2 added new parameters $event_id and $order_id
		 * @since 4.5.5 changed filter name to be unique to non attendance emails
		 *
		 * @param string  email content
		 * @param int     $event_id The event ID.
		 * @param int     $order_id The order ID.
		 */
		$content = apply_filters( 'tribe_rsvp_non_attendance_email_content',
			tribe_tickets_get_template_part( 'tickets/email-non-attendance', null, $template_data, false ),
			$event_id,
			$order_id
		);

		$sent = wp_mail( $to, $subject, $content, $headers, $attachments );

		return $sent;
	}