- Chg: Added `View::viewFile` and removed `ViewEvent::viewFile` (qiangxue)
- Chg: Changed `Controller::afterAction()`, `Module::afterAction()` and `ActionFilter::afterAction()` to pass `$result` by value instead of reference (qiangxue)
- Chg: `yii\base\Extension::init()` is renamed to `bootstrap()` (qiangxue)
- Chg: `getComponent()` and `setComponent()` in `Application` and `Module` are renamed to `get()` and `set()` respectively. (qiangxue)
- Chg: The signature of `Yii::createObject()` is changed. Constructor parameters must be passed as the second parameter. (qiangxue)
- Chg: `Yii::$objectConfig` is removed. You should use `Yii::$container->set()` to configure default settings of classes. (qiangxue)