There are ACME clients written in Python 2 or even pure shell -- should work even on very old systems (but not older than ~2010, you need openssl with TLS1.2 su

There are ACME clients written in Python 2 or even pure shell -- should work even on very old systems (but not older than ~2010, you need openssl with TLS1.2 support). I personally prefer them even on current systems, as I don't really like the "automagic" nature of certbot.