What software are you using? You've posted in the forum Lounge which isn't software-specific. The Lounge is where you can connect with your peers for conversations that don't directly relate to product help and support.
Let us know what software you're using and a moderator can move your thread to the appropriate, software-specific, support forum.
It's likely that there is a way to open older files in newer versions.
That being said, you can install older versions of software via the CC app all the way back to (and including) CS6, so it's likely you can get a version that will easily open your files. This link explains how to get older versions installed.