Upgrade Existing Yii 1 Project to Yii v.2

General information for the website: We are running an on-demand delivery platform
Kind of development: Customization of existing website
Description of every page/module: I bought the existing platform from Codecanyon https://codecanyon.net/item/kartero/17465109 as we found that the solutions and the existing modules in this platform already fit to what we want. However, the system is already built on top of Yii V.1 framework and we found that integrating new library via composer & other staffs like asset management ... etc. or something else is quite challenging and time consuming.

I need to Upgrade the framework from Yii V.1.1 to Yii V.2. I found some documents on Yii official website:
http://www.yiiframework.com/doc-2.0/guide-intro-upgrade-from-v1.html
Description of requirements/features: + Has background in Yii V.1 framework
+ Has experience working with Yii 2 & Laravel framework
+ Some parts we need to refactor like in Controller they mix the code together into one file.
Extra services needed: Installation, Security
Similar urls: http://bastisapp.com/kartero/
Extra notes: