The zipped folder contains only the new version 2.18 filter plugin. If you need the associated joined-up True Type fonts please search for the version 2.17 update and download and install those to your user fonts folder as well.

Download and install the plugin to your plugin folder and remove the old one.

The update addresses the following issues:
Fixes the error generated with Custom-xcf-Fonts when using more obscure keyboard characters defined in the xcf file
Improves error handling for missing layers in Custom font files
Adds more information shown with layer labels (see attached image) in the toolbox
Reversed path now removed from the path list after use