There are more reasons for the incompatibility, and I would not limit the use of Capttivate Classic to older projects.

At this moment you can only create responsive projects with the new version. As you are probably aware of from the Fluid Boxes projects in the present version, that comes with quite a lot of limitations. If you don’t want to accept those limitations and don’t need a responsive project for any reason, please keep to Captivate Classic even for new projects.

Same recommendation if you have built Libraries with assets and Shared actions, custom Themes for your company brand, question pools to reuse, you will need Captivate Classic at this moment. I just mentioned a couple of features which are still missing in the new version.

Hello Debra221909279lab thanks for reaching out and for your query. Your older projects will not be compatible with the all-new Adobe Captivate. The two versions have been developed in two different technology stacks and even the file types are different. However, our team is committed to ensure that your current workflows are not disrupted. Therefore, for some time to come, we will continue to support Captivate 2019. You will have access to both versions of the product so that you can work on your existing projects as well as new ones.