This is never been an advertised feature of Carbon nor it has been recommended. Hence you can't expect to have backward compatibility for a "non feature".
The right thing to in a production environment is to use a web server (Apache, nginx etc...) to serve static files because web servers are optimized to do that. Then proxy the connections to Carbon via the web server. For example, by using mod_proxy for Apache.
You can still use the Application Server (or after installing AppServer features into any Carbon server) to create a .war file and have your static site there. Then again if it's a static site using Application Server is an overkill.