How do I keep previous versions of an Adobe CC application as I install the new one?
What is the trick? On install, select "Advanced Options" and uncheck "Remove Previous Versions". That's it! And you'll keep your older versions of InDesign (or Photoshop, or whatever).
How do I get back a previous version of an Adobe CC application that was unintentionally removed?
Adobe has answered this really well here. We hope you don't wind up there, but the bottom line is that earlier versions of Creative Cloud are easily available as needed. It really is quite simple: