Codeigniter 4 - composer update to v4.4 issues

Just ran composer update, upgrading to CodeIgniter v4.4 Now Codeigniter does not work, the log shows the error:

PHP message: PHP Fatal error:  Uncaught Error: Undefined constant "CodeIgniter\ENVIRONMENT"

Solution

Upgrade to CodeIgniter 4.4

The following files received significant changes and you must merge the updated versions with your application:

public/index.php
spark

If you have not changed index.php or spark, just copy the new versions of these files from the v4.4 framework. Otherwise, merge the new versions with your current files.

cp vendor/codeigniter4/framework/public/index.php public/index.php
cp vendor/codeigniter4/framework/spark spark

After fixing the above, you may still have to update some Config files. Check the following Config changes-:

Uncaught ErrorException: Undefined property: Config\App::$allowedHostnames in /home/dev/src/php/providr/vendor/codeigniter4/framework/system/HTTP/SiteURIFactory.php:246

App/Config/App.php

Check there is a $allowedHostnames property in the App class. If you want to accept multiple Hostnames, set this property to your hostnames.

public array $allowedHostnames = [];

The property $proxyIPs must be an array. If you don’t use proxy servers, it must be

public array $proxyIPs = [];

app/Config/Routing.php Routing.php is a new Config file which holds settings that used to be read from Routes.php.

Copy app/Config/Routing.php from the new framework to your app/Config directory, and configure it. Remove all settings in
app/Config/Routes.php that are no longer needed.
If you use the environment-specific routes files, add them to the $routeFiles property in app/Config/Routing.php.

Hopefully CodeIgniter will now fire up. But also check the following files which have changes: app/Config/Cookie.php app/Config/Security.php app/Config/Session.php

For full details of all v4.4 changes see CI4 docs - upgrade to v4.4