Shibboleth is designed to be maximally interoperable with other implementations of the technical specifications and profiles that it supports. However, standards never address every detail that goes into a successful deployment of feature-rich technologies, and implementations often focus on different features, or provide for limited flexibility in areas that their implementers find to be unimportant or uninteresting. Needless to say, implementers often disagree about what's important. As a result, interoperability can often be challenging in practice or limited in areas that industry profiles have yet to address.
Where information is known or made available about issues or configuration changes needed with other software products, we will collect it here. We encourage (in fact we need) deployers of non-Shibboleth software to assist in this process.