In the short-term, seems like the best thing Clarivate could do for its customers is to make X9 freely available to all with an EN20 license. There was much loss of functionality in v20, I doubt the coders can track it all down. EndNote has a loyal, worldwide user base, but EN20 is a loyalty killer. Even if all Clarivate intends to do is spin off EndNote, it’s a lot more valuable with its user base than without.
Thus suggestion stems from my recollection during installation is that the libraries are compatible between X9 and EN20, but not the earlier versions. True?