SAML plugin 1.0.4 not compatible with our configuration and/or CERN SSO

The latest SAML plugin seems to not be compatible with either CERN's SSO implementation or with our own Jenkins configuration.

Accessing a Jenkins instance with the wrong version of the plugin prints a stacktrace.

Also, the SAML plugin version we use has a security advisory (although we are not affected) that displays in red in the header of the Jenkins instance. This urges users to upgrade this and break their applications.