Version 3 has been re-written and re-designed completely from scratch. Here are the key changes in v3:
CoreUI and Bootstrap components have been prefixed. If you add Bootstrap or CoreUI CSS to your existing project, it can conflict with your existing CSS or the third party components styles creating a mess in styles and destroy the layout of your project. That’s why we decided to add c- prefix to each class to avoid CSS classes collision and isolate CoreUI’s styles and scripts.
New design to meet Web Content Accessibility Guidelines requirements. CoreUI 3 make web content more accessible to people with disabilities and meets the needs of individuals, organizations, and governments internationally.
Introduce new components libraries for Angular (@coreui/angular), React.js (@coreui/react), and Vue.js (@coreui/vue). The third party components libraries ngx-bootstrap, reactstrap, bootstrap-vue, are deprecated. Since version 3.x our libraries contain not only our components but also cover all Bootstrap’s elements.
We need your help to make CoreUI the best it can be. The source code for version 3 will be available in a v3-next branch on GitHub. We looking forward to your feedback.