Features from DGN files can imported using the DGNRuleFile.xml mapping file. The file is located C:\Program Files\CARIS\Caris\<version>\modules\Feature Editing\. You may want to refer it the file when reviewing this section.
support\Rules
The following diagram provides an overview of the DGN mapping file structure.

The <ObjectToObjectConversionTable> contains the Version attribute. The Version is the version number for the file.