'Return versions supported prior to the microversions epoch.'

@index.api_version('2.0')
def index(self, req):

    builder = views_versions.get_view_builder(req)
    known_versions = copy.deepcopy(_KNOWN_VERSIONS)
    known_versions.pop('v1.0')
    known_versions.pop('v3.0')
    return builder.build_versions(known_versions)
