it is supported, anything with SAML2.0 as an IDP is supported, i have tested it in my lab with 11.6 version as well.
Below points you need to consider
The following are the expectations from SAML Response:
• The entire SAML response (message and assertion) is signed or only the message is signed but not the
SAML assertion alone is signed.
• SAML Assertion must not be encrypted.
• SAML response must be signed using SHA-128.
• NameIDFormat in SAML response must be urn:oasis:names:tc:SAML:2.0:named-format:transient.
• uid and user_principal attributes should be present in SAML assertion in the AttributeStatement section.
The "uid" attribute value must be the user Id using which users log in to Cisco contact centre applications
that are SSO enabled and the "user_principal" attribute value must be in uid@domain format
