fix(#1105): certbot only works on CHT 4.2, instruct to use own domain

* Denote certbot only works on CHT 4.2 or later
* specify static ip, specify need to change domain in .env file

content/en/apps/guides/hosting/4.x/adding-tls-certificates.md

@@ -54,9 +54,12 @@ Your certificates are now safely stored in the native docker volume. Restart you
 
 ## Certbot certificate
 
-_The Certbot integration requires CHT 4.2.0 or later_
+_This Feature available on CHT 4.2.0 or later_
+
+If you have a deployment with a static, public IP and a domain name pointing to that IP, you can have Certbot automatically create free TLS certificates by using [their Docker image](https://hub.docker.com/r/certbot/certbot/). 
+
+Assuming your CHT instance is running with the default self signed cert. Be sure to change `cht.example.com` to your domain first though:
 
-If you have a deployment with a publicly accessible domain name, you can have Certbot automatically create free TLS certificates by using [their Docker image](https://hub.docker.com/r/certbot/certbot/). 
 
 Assuming your CHT instance is **already running with the default self-signed cert**:
 
@@ -94,7 +97,7 @@ Assuming your CHT instance is **already running with the default self-signed cer
    EOF
    
    cat > .env << EOF
-   DOMAIN=deleteme2-certbot-nginx-cht.plip.com
+   DOMAIN=cht.example.com
    STAGING=
    CHT_SSL_VOLUME=cht_cht-ssl
    TZ=America/Whitehorse