> We are installing Prosody IM, the community modules and certbot (to get certificates).

My understanding is that certbot is part of letsencrypt which is going to eventually make it so you cannot use XMPP certs or did I misunderstand this?

https://news.ycombinator.com/item?id=46950780

The blog post you are referencing explains the changes the XMPP community has to do to keep up with what Lets encrypt did. TLDR: People just need to upgrade their servers.