| Yii | Yii2 |
|---|---|
| Yii requires PHP 5.2. | Yii 2.0 requires PHP 5.4.0 or higher, which makes use of the latest features of PHP. |
| In Yii, prefix C was used, and the classes were in global namespaces. | In Yii2, prefix C is not used in namespaces. And classes based on the directory structure. |
| Yii uses the On-event method, where custom event names are not allowed to use. | In Yii 2.0, any name can be used for the event with a handler attached to it, and event handling can be done using J-query. |
| Yii uses PHP as the primary template language. | Yii 2.0 is equipped with PHP and two more template engines- TWIG and SMARTY. |
