with the exception of some acrobat/reader versions, older adobe programs coexist with newer versions without problem.
on the other hand, it would make no sense to, for example, install lr5 from cc if you already have a licensed copy of lr5 on your computer. ie, do not install the same version via perpetual license and cc subscription.
Thanks very much for your reply. That helps me out.
p.s when using the adobe forums, please mark helpful/correct responses, if there are any.