https://github.com/reduxjs/redux/releases/tag/v4.2.0 Redux v4.2.0リリース。 @reduxjs/toolkitへの移行を促すために、createStore APIをDeprecatedにして、legacy_createStore APIを追加。 関連URL Mark `createStore` as deprecated · Issue #4325 · reduxjs/redux Why Redux Toolkit is How To Use Redux Today | Redux