I’m using the SAML-Plugin to connect to a keycloak instance.
Since the last update the logout is not working. I just get a Not Implemented on the /auth/saml/spslo site when clicking ‘Logout’. When going back in browsers history I’m still logged in.
I’ve found this PR in the repo stating the same issue.
I am experiencing the same issue. Any updates on this?
I’ve just merged this, so please give SLO another try and let us know how you get on. The variable rename in discourse-saml is described as being backwards-compatible, but perhaps that’s not entirely true for the SLO case. 
Sorry for the late reply. The change works for me. thanks! 