Please enable a version of InDesign CC2017 that can be installed on macOS Catalina. It causes problems for large book files when they have to be converted to newer versions of InDesign. It often takes a long time from start to finish for a book project. When a file is created in one version of InDesign, it should be kept in that same version until it is completed, to avoid unintended errors and discrepancies creeping in. I have many files that originated in CC2017, which I now cannot open on a new machine operating with macOS Catalina.