Two known issues that affect some CAS clients (in particular, older Jasig Java CAS Clients):
- Cannot parse SAML 1.1 response due to "soap11" SOAP envelope namespace prefix. The client expects a hard-coded string, "SOAP-ENV."
- The Response element lacks some required attributes.
While 1 is pretty clearly a client limitation, it's prominent enough that it's just easier to make the IdP comply with what (broken) clients expect. 2 is clearly a bug.