Upgrade Codeigniter 3.1.6 to 4.1.9

I have a admin panel made with Codeigniter 3.1.6 version. I searched it but i found different opinions about it. Can i upgrade it to 4.1.9? I have site settings, image uploading, mail sending and some different things in my project. (iziToast, sweetalert, toggle button)

Solution

I believe this is a big endeavor but nonetheless - this should give you some structure and pointers - Upgrading CodeIgniter 3 to CodeIgniter 4

While most is generally to Filetype (Model, View or Controller) and specific upgrade and/or omissions of libraries and in few areas extensive changes might be needed in your code.

Most of the changes must be from Models as more of CRUD Functionality is built-in available, while Configuration Files is completely different than CodeIgniter 3. I believe part by part some areas might be tricky. Wishing success ahead with new features and Built in ORM.

P.S. - Myself am beginner in CodeIgniter 4 only.

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