I'm trying to run a Grails Application from [the Grails In Action website](http://www.manning.com/gsmith2/). I've imported the 'hubbub' project into the GGTS app and have encountered build errors. The project was originally built with Grails 2.3.7 whereas I have version 2.4.4 on my system. Based on [another Stack Overflow question](https://stackoverflow.com/questions/2034023/how-do-i-upgrade-the-grails-version-for-an-existing-application) I've changed the '*app.grails.version*' in the *application.properties* file to grails version 2.4.4 which prompted a flurry of downloads in the command prompt terminating in a series of errors regarding problems with plugins. I can't run the app because I'm told that "Project 'hubbub' is missing required source folder: grails-app/utils". If I try to change '*app.grails.version*' back to 2.3.7 I'm told that I need to configure a Grails installation of 2.3.7. 

Am I doing something wrong here in trying to upgrade this Grails project? Or do I really have to install Grails 2.3.7 in order to get this to work?

(Sorry, I haven't posted the errors regarding plugin downloads but I can't seem to recreate them).

Thanks in advance!