InDesign CS6 reverted to trial status, though downloaded under Creative Cloud licence

Hi! I've looked but not found this exact topic elsewhere in the forum, so please forgive any duplication.

I downloaded InDesign CS6 from Creative Cloud in 2017 (deliberately, as an older version). I have a valid current subscription to Creative Cloud. However just a few days ago I started getting a warning notice whenever I started InDesign CS6, with a countdown telling me how many days I had left of a 30-day trial period. Apparently the program has been reverted to trial status, and there is now no provision for me to download a later version without first uninstalling it. (That's the only option provided in Creative Cloud Desktop.)

I use the CS6 version deliberately, because I work with people who have even older versions; and the publishing software I use requires the same version in order to open a previous job: i.e., I cannot open older documents using a later version (hard to explain briefly—can give more details to anyone interested). I am running it on Windows 7, and I have found that more recent versions do not work as well for me in that environment, for various reasons.

I therefore really need to continue using CS6. Is there any way I can get it taken off the trial system to allow this, and also to allow me at the same time to try out a later version? (I.e., so that there are more options for InDesign than simply "Uninstall"!)

Many thanks for any help anyone can give!