Problem with DigitalOcean 1click install image

Just attempted to set up Mastodon on DO with the 1 click install image. Was working my way through the nice script that fires on ssh login and things were going well when the follow error occurred:

An unexpected error occurred:
The client lacks sufficient authorization :: Account creation on ACMEv1 is disabled. Please upgrade your ACME client to a version that supports ACMEv2 / RFC 8555. See for details.

Now I’ve gone to LetsEncrypt and read up on the error and I understand what’s happening. What I don’t know, is how to fix it.

Anyone have time to help out a newb?