react-addons-css-transition-group

The code in this package has moved. We recommend you to use CSSTransitionGroup from react-transition-group instead.
In particular, its version 1.x is a drop-in replacement for the last released version of react-addons-css-transition-group.
Run npm install --save react-transition-group@1.x, and replace the imports in your code:

// Old
import CSSTransitionGroup from 'react-addons-css-transition-group';

// New
import CSSTransitionGroup from 'react-transition-group/CSSTransitionGroup';

The documentation branch for react-transition-group@1.x can be found here.