* Fixed issue [#890](https://github.com/jakubpawlowicz/clean-css/issues/890) - adds toggle to disable empty tokens removal.
* Fixed issue [#893](https://github.com/jakubpawlowicz/clean-css/issues/893) - `inline: false` as alias to `inline: 'none'`.
* Fixed issue [#905](https://github.com/jakubpawlowicz/clean-css/issues/905) - allows disabling selector sorting.
+* Fixed issue [#906](https://github.com/jakubpawlowicz/clean-css/issues/906) - improves usability of web UI settings.
* Fixed issue [#908](https://github.com/jakubpawlowicz/clean-css/issues/908) - improved `minify` method signature.
* Fixed issue [#916](https://github.com/jakubpawlowicz/clean-css/issues/916) - maximum number of merged selectors.
* Fixed issue [#920](https://github.com/jakubpawlowicz/clean-css/issues/920) - allows skipping certain properties in level 2 optimizations.
* `skipProperties` flag in level 2 optimizations controlling which properties won't be optimized;
* new `animation` shorthand and `animation-*` longhand optimizers;
* `removeUnusedAtRules` level 2 optimization controlling removal of unused `@counter-style`, `@font-face`, `@keyframes`, and `@namespace` at rules;
+* the [web interface](https://jakubpawlowicz.github.io/clean-css) gets an improved settings panel with "reset to defaults", instant option changes, and settings being persisted across sessions;
## Constructor options