Versioning in Custom Tables

There is no versioning for custom table data. You could create a global event handler to create an audit log for you. You'd have event handlers for insert, update and delete records on specific custom tables you want. I'd log this data in a custom module table then that you can view. The downside of this is it won't have any of the functionality to roll back to a specific version, it will simply create a log for you with the existing data.

Brenden is correct, if you want versioning in a true sense you will need to create a custom module class and enable versioning on the object type info, and set up your ui pages properly. In Kentico documentation it describes how to set versioning on custom classes.