After downloading and installing X5, I have noticed that my version of X3 is still on the computer. I'm used to upgrades overwriting and/or deleting previous programs.
Can anyone tell me if there is any advantage to keep X3 on my computer? I would think that X5 would be able to handle previous X3 projects, but I don't want to assume anything.
Even though you may have bought an upgrade version, it is in fact a full and distinct version not dependent in any way on previous versions already installed, apart from having the latter's serial number to establish that you were entitled to the upgrade price. Thus your version X3 will continue to function fully, as well as X5 -- though you can only open one or the other at any one time.
But given the problems with X3, and particularly the schemozzle with its burning module, I would feel no pain in uninstalling it if space is a consideration. And yes, X5 can certainly open X3 projects.