If you want to import your settings from the last "Clover" version, export your settings to "exported_clover_settings.json", then rename that file to "Kuroba_exported_settings.json". Stick that file in the Kuroba save folder and import your settings.
Changelog from v4.0.0
Changelog from v4.0.1
Fixed:
- Thumbnail views not being removed due to a refactoring oversight