README.md in acme-client-2.0.4 vs README.md in acme-client-2.0.5

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+ new
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 # Acme::Client
 
 [![Build Status](https://travis-ci.org/unixcharles/acme-client.svg?branch=master)](https://travis-ci.org/unixcharles/acme-client)
 
-`acme-client` is a client implementation of the [ACMEv2](https://github.com/ietf-wg-acme/acme) protocol in Ruby.
+`acme-client` is a client implementation of the ACMEv2 / [RFC 8555](https://tools.ietf.org/html/rfc8555) protocol in Ruby.
 
 You can find the ACME reference implementations of the [server](https://github.com/letsencrypt/boulder) in Go and the [client](https://github.com/certbot/certbot) in Python.
 
 ACME is part of the [Letsencrypt](https://letsencrypt.org/) project, which goal is to provide free SSL/TLS certificates with automation of the acquiring and renewal process.