def action_oldest(app) -> None:
    """Show the previous email message by finding the next lower ID from the list of envelope IDs."""
    try:
        if (app.reload_needed):
            app.action_fetch_list()

            ids = sorted((int(envelope['id']) for envelope in app.all_envelopes))
            app.current_message_id = ids[0]
            app.show_message(app.current_message_id)
            return

        else:
            app.show_status("Failed to fetch envelope list.", severity="error")
    except Exception as e:
        app.show_status(f"Error: {e}", severity="error")