The only supported version of Creative Suite is CS6.
Activation is still required for CS3 and later. There are activation
free downloads of CS2 available for anyone that has a CS2 license and
still needs to run it.
Thank you for the fast response, Bob. I work for a company that provides InDesign plug-ins, and this will help determine how long we continue to make enhancements in our plug-ins for older versions of Creative Suite. We have customers using CS2, 4, 5, 5.5 and 6, with a Creative Cloud installation on the horizon.
That will be your call internally, but remember that older version
Creative Suite are not getting any updates and I was very surprised to
even see a CS6 update to InDesign a few weeks back.