allowing the next order coupons for particular order emails only

snippet-noc-for-particular-order-status.php

add_filter('rnoc_before_displaying_next_order_coupon','rnoc_before_displaying_next_order_coupon',10,2);
function rnoc_before_displaying_next_order_coupon($message,$order){
    if (method_exists($order, 'get_status')) {
        $order_status = $order->get_status();
        $order_status = strtolower($order_status);
        if($order_status == "processing"){
            return $message;
        }else{
            return '';
        }
    }
    return $message;
}