The hotfix includes two files:
• DgnLsPurge.dll. Once loaded, it allows you to purge DGN objects using the DGNPURGE command.
• AcDgnLS.dbx. This keeps the DGN objects from propagating to new files when copying, pasting, or inserting from other files.
Refer to the associated readme files for instructions. Most likely the hotfix files will need to be unblocked in order to work and there is a screen shot about this in the readme.