Saving Packaged Illustrator CC file

I have created a project within Illustrator CC (However, I am not too familiar with this program). My client has a later version of Illustrator (CS4) and wishes to be able to open it in their office. When saving it as a general Illustrator file, he is able to open it when I save it as an IDML. However, when packaging the project in CC, I cannot chose this option (IDML CS5 or later) and they are left being unable to open the file. What can I do?