First go through this repo to get the complete idea of using Yii2 with yii1: https://github.com/ahmadasjad/yii1plusyii2

• add return before render('yourView', ['model' => $model]) call inside every controller. **
• Remove echo from your controller, and return all the echo part with a single return statement **
• Add echo before every widget call inside the view **