FIY all 3 specifications in $sub are on track to be finalised soon. Session management - we're mostly here I believe, but need to run conformance tests Front-channel - we don't have this, so contributions would be welcome Back-channel - we have something similar, but doesn't follow the spec. So we need to fix this. Could introduce a new endpoint that is spec compliant and deprecate the old. Or we morph the old endpoint into the new, which may be more awkward for users, so my vote goes to new compliant endpoint.