And ... how many configuration flags do you need to store in the config that are required in app logic so that you have to access the ConfigHolder ? I moved a large app from Grails 2.3.7 to Grails. 3.2.11 and went through this, but I did not have to make drastic changes to the application. What kind of data should be stored in config so that you need to use the Holder to access that data ? In my case, I keep it as light as possible. I think I use it in only one place.