When I delete a project, I am presented with a list of multiple versions of my project. Why is this?

Sinolta configuration files are stored under
\\Sinolta Projects\\configuration\\….
The version number corresponds to the version of Sinolta at the time of saving the project configuration. This basically means that when Sinolta saves its configuration, it keeps it under a folder that is specific to that version.
After upgrading Sinolta, the older version of configuration will remain in the old subfolder, and when you upgrade the project, it copies the old configuration into the new folder under the current version dn then performs the conversion.
Every time you upgrade Sinolta, you will leave a copy of the project configuration for the old version of Sinolta.
When you try to delete a project, Database Builder is showing you a list of all versions of your selected project.