Hello @hbrls,
Regarding X1 and X3, they are just the names of the intermediate certificates. You can see them here https://letsencrypt.org/certificates/
Anyway, you don’t need to issue a new certificate with the updated script (yes, update the script to the new version) but you only need to concatenate your current cert and the new intermediate cert https://letsencrypt.org/certs/lets-encrypt-x3-cross-signed.pem into lisitede.chained.crt
Cheers,
sahsanu