backstage/.changeset/kind-walls-speak.md

@backstage/backend-defaults

@backstage/backend-defaults
minor

BREAKING: The backwards compatibility with plugins using legacy auth through the token manager service has been removed. This means that instead of falling back to using the old token manager, requests towards plugins that don't support the new auth system will simply fail. Please make sure that all plugins in your deployment are hosted within a backend instance from the new backend system.