When you open a project or project suite created in an earlier version of TestComplete, you are prompted to convert it to the format used by the current version of TestComplete. The project (project suite) is converted in place, by replacing the original files. Optionally, you can choose to create a backup copy before conversion.
Once converted, the project (project suite) can no longer be opened in earlier versions of TestComplete. We recommend that you select the Back Up and Convert option so that you have a backup of your project (project suite).
See Migrating Projects Created in Earlier Versions to TestComplete 15 for more information.