It's unfortunate to see this go away, but understandable given the costs involved. Another option is to run Caddy as a web server, which provides automatic cert renewal (https://caddyserver.com/docs/automatic-https). If notifications are still important, they also provide an event subscription system (https://github.com/caddyserver/certmagic#events) so you can subscribe to cert-related events, run custom code, trigger event handlers, etc.