composer require yiisoft/yii2-bootstrap4 not working - How to install Bootstrap 4 in yii2

composer require yiisoft/yii2-bootstrap4

Yii2 - Upgrading to Bootstrap 4

Please following the following steps to install Bootstrap 4 and uninstall old version of Boostrap.

Make sure you are in the Project Directory.

//-- If this line doesn't work: --/composer require yiisoft/yii2-bootstrap4//-- Then use the following command: --/composer require --prefer-dist yiisoft/yii2-bootstrap4And to remove old one run the following:composer remove yiisoft/yii2-bootstrap