CI4 upgrade from version 4.2.1 to 4.2.6

try the command : composer create-project codeigniter4/framework  and see what you get !

Sorry, it is completely a mistake. You should not install like that.
Because you cannnot update CI with `composer update`.

We have only two choices if we install via Composer.
composer create-project codeigniter4/appstarter project-root
composer require codeigniter4/framework
See https://codeigniter4.github.io/CodeIgnit...poser.html

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