From HFML-FELIX Wiki
certbot register --server https://acme-v02.harica.gr/acme/<SNIP>/directory --eab-kid <SNIP> --eab-hmac-key <SNIP> --agree-tos --no-eff-email --email victor.claessen@hfml-felix.nl
Then to request certificates
certbot --apache --server https://acme-v02.harica.gr/acme/<SNIP>/directory