Regarding installing older versions

I've been struggling with an issue we have with our customers for a number of years now with Creative Cloud so I figured I'd ask here if anyone has any tips or possibly a solution.

Our conundrum is that we have a large user base which use InDesign/InCopy and they need to have the correct versions installed for our workflow to function. For a number of reasons our system doesn't support the newest release of CC from day one. (Currently the majority are on CC2017.) This means that there is a period of time after each new Adobe release where our users need to install a previous version. What we've seen from our support cases is that a full 20% are related to installing InCopy because the customer (or more commonly their IT departments) has simply installed the latest version. (Even when they are given explicit instructions  to install a previous version.) Many say that there is no way to install older versions or assume that all "CC" versions are the same and the latest is the best.

What I'm wondering is - is there an easy way to direct users to download an older version of InCopy other than to tell them to subscribe to Creative Cloud but don't click the link in the email they receive to download it - as this will automatically install CC2018. Instead they should download the desktop app separately and then use the "Previous versions" option on the download button to select the correct version.

I guess what would be ideal would be some sort of link that could be used that would direct to the correct version. I know we can't ourselves deliver a packaged version of InCopy to our customers due to licensing (even if they are still required to have a subscription) otherwise this would be an easy way to resolve the issue.

Has anyone else had a similar issue? I gather this is probably only a problem with InCopy/InDesign as the other Adobe applications are less sensitive to the version number.

Thanks for any help with this.