I have found that the version by mheder on github (https://github.com/mheder/liferay-shibboleth-plugin) also implements very useful features:
-auto create users using Shibboleth attributes (email, first name, last name)
-auto update user information upon login
-added options to specify the headers (Shibboleth attributes) to be used for extracting email, first name and last name
-basic attribute to role mapping
Following the testing issue https://issues.liferay.com/browse/LPS-42880 it seems that this only works when Shibboleth is deployed on the same Servlet Container?
It is unclear how Liferay redirects /c/portal/login to eg: sso.liferay.com.
Any information on the basic installation of that Shibboleth would be nice