Can you kindly clarify how to find out what validation method is used by my Certbot installation? I did not install Certbot on our server.
I think Letsencrypt has left its users partly hanging here, with no pointer to figuring out if anything at all needs to be done, and incomplete instructions in case something needs to be done. Having said that, Letsencrypt/Certbot looks like a great idea, but important changes like this need better support to the users.