Yii 2 - Upgrade to bootstrap 4
There is no return to bootstrap 3!
Yes it is! If you upgrade your Yii 2 assets on your installation, there will be many difficulties to use the bootstrap 3 css and js files using the Yii 2 assets. So be sure you need bootstrap 4 only for your projects. First of all we update the dependencies on our composer,json file.
That's all but now we will have another problem. We have to update the configurations of our frontend project. On your config\main.php:
'components' => [
'assetManager' => [
'appendTimestamp' => true,
'linkAssets' => false,
'class' => 'yii\web\AssetManager',
'bundles' => [
'yii\web\JqueryAsset' => [
'js' => [
YII_ENV_DEV ? 'jquery.js' : 'jquery.min.js'
'yii\bootstrap\BootstrapAsset' => [
'css' => [
YII_ENV_DEV ? 'css/bootstrap.min.css' : 'css/bootstrap.min.css',
'yii\bootstrap\BootstrapPluginAsset' => [
'js' => [
YII_ENV_DEV ? 'js/bootstrap.js' : 'js/bootstrap.min.js',
If you use Admin LTE, you CANNOT upgrade your app to boostrap 4 because the bootstrap 4 assets will not work with Admin LTE. You have to build your new admin area with a bootstrap 4 admin template and it will not be easy. There are many amazing templates available online but I am not sure you will have a lot of time to work on a new admin area and integrate into your PHP application. I am sure there will be a lot of work. We don't have to reinvent the wheel so I think we will continue to use AdminLTE and bootstrap 3 in this case.