In the Yii V2.0 docs is described the BootstrapInterface stating:

BootstrapInterface is the interface that should be implemented by classes who want to participate in the application bootstrap process.

It goes on to show:

The second approach is used by application code which needs to register some code to be run during the bootstrap process. This is done by configuring the yii\base\Application::bootstrap() property:

return [

    // ...

    'bootstrap' => [



            'class' => "path\\to\\MyBootstrapClass2",

            'prop1' => 'value1',

            'prop2' => 'value2',




This returns the following error:

Unknown Property – yii\base\UnknownPropertyException

Setting unknown property: yii\web\Application::bootstrap

What gives?

Ok, I see this was changed just 6 days ago from ‘preload’ to ‘bootstrap’.

Downloading latest version and will try again!