Probably a Basic Mac OS Question


I'm new to the Mac and notice that for both Logic Studio and Mainstage, there are two applications. For example I have Mainstage.App and Mainstage I use and it appears to have the latest version #. I tried running the version and it told me that the Concert I had created was not compatible with this version and in the About section it was an earlier rev. Does Apple keep the old version of the application when doing an update, which I did after installing form the CD? Would I be safe in deleting the in each case?