error update form 4.3.7 to 4.4

If you use v4.3.7, read the all related upgrading guides and do the things needed:
https://codeigniter4.github.io/CodeIgnit...e_438.html
https://codeigniter4.github.io/CodeIgnit...e_440.html
https://codeigniter4.github.io/CodeIgnit...e_441.html
https://codeigniter4.github.io/CodeIgnit...e_442.html
https://codeigniter4.github.io/CodeIgnit...e_443.html

Thanks for you're reply!
I have found out that I am using version 4.3.6.
My question is should Composer have taken care for a smooth upgrade? 
Now I have to rebuild 3 different projects from the ground, that cannot be the intention of (using) a framework?

In fact, there are not so many changes. Most of the documentation correction.
In order not to complicate the update process, it is advisable for you to match the latest version (as it comes out). Agree, it's terrible if someone updates from version 2.x to 4.x?

Simple CI 4 project for beginners codeigniter-expenses ( topic )

What I recommend is:
- use Composer and Tatter Patches https://github.com/tattersoftware/codeigniter4-patches
- learn how to use git
- update every version as soon as possible

ci-phpunit-test | CodeIgniter Testing Guide | CodeIgniter 3 to 4 Upgrade Helper

HI Kenjis, thanks for your reply!

Your advices are good on it self:
I decided to start from scratch, download the latest version and build up from start.
Running from one error to another.... auhorisation issues with github and so on and.

Instead of building great projects I am spending days and days reading documentation, pages and pages on forum with half, wrong or no solutions other than people telling "it works"
loosing fun of coding here.

I had to rebuild everything and manually adjust all the data from the appstarter, now it is working again, thank you very much for your help.

I put a copy from vendor/codeigniter4/framework/public/index.php to public/index.php > solved "Undefined constant "CodeIgniter\ENVIRONMENT" problem