Version 2 of sslscan includes a major rewrite of the backend scanning code, which means that it is no longer reliant on the version of OpenSSL for many checks. This means that it is possible to support legacy protocols (SSLv2 and SSLv3), as well as supporting TLSv1.3 - regardless of the version of OpenSSL that it has been compiled against. It is still recommended to build statically where possible, but dynamically built version should be significantly more useful.
Note that there are also some breaking changes to the XML output, which are documented in the readme.
This rewrite been made possible largely by the work of jtesta, who has been responsible for most of the backend rewrite.