I’ve been using Cubase LE4 for a little over a year, and read about the CC121 … which looks like a great device to improve the user interface with the software.
I see that the CC121 comes bundled with Cubase AI4. Does this replace Cubase LE4 for me? Do I need to use AI4, or can I continue using LE4?
You will have to use AI4 to use the functionality of the CC121. As far as I am aware, LE4 and AI4 are identical featurewise, with the exception of the support for AI hardware.
Installing AI4 should be possible seperately from LE4, and I think both licenses can be used alongside eachother. If you unregister your LE4 license you should be able to use it on another computer/give it to a friend etc.