I’ve released a new version of the stimulus-rails gem as version 0.3.0 without the prototype importmap mechanics, but that instead relies on what’s been made available by importmap-rails. This is a breaking change. You will need to install importmap-rails, then reference @hotwired/stimulus-autoloader via the importmap to continue, if you’re upgrading from a previous version and use the asset pipeline.
I’ve also released a new version of the turbo-rails gem as version 0.7.0 where the asset pipeline installer assumes that importmap-rails is available. No changes if you’re using this together with Webpacker.