I also noticed. Upgrade from 7.21.3 to 7.22rc2 yesterday. I had a still valid LE certificate before upgrading. It was issued by /certificate/enable-ssl-certificate some versions ago for the "mynetname" domain. After upgrading there was an additional acme_cert_xxxmynetname certificate. I just deleted the previous one and assigned the new one manually to /ip/services. But I think this kind of migration should be done automatically.
Until 7.21 it was possible to use /certificate/enable-ssl-certificate to generate a LE certificate for the mynetname domain. It also supported LE dns-01 challenge. But now the command prints:
progress: [error] ACME certificates have moved to 'certificate' component. Please use /certificate/add-acme command
But the add-acme command requires a directory-url. Following seems to work, even without opening port 80 to wan:
/certificate/add-acme domain-names=xxx.sn.mynetname.net directory-url=https://acme-v02.api.letsencrypt.org/directory
Other than that, I like the add-acme command. As I use my own CA (step-ca) which supports ACME, I can now issue certificates directly from ROS. Pretty nice addition. 