############################# Upgrading from 4.2.0 to 4.2.1 #############################

Please refer to the upgrade instructions corresponding to your installation method.

:ref:Composer Installation App Starter Upgrading <app-starter-upgrading>
:ref:Composer Installation Adding CodeIgniter4 to an Existing Project Upgrading <adding-codeigniter4-upgrading>
:ref:Manual Installation Upgrading <installing-manual-upgrading>

.. contents:: :local: :depth: 2

Mandatory File Changes

app/Config/Mimes.php

The mapping of file extensions to MIME types in app/Config/Mimes.php was updated to fix a bug. Also, the logic of Mimes::getExtensionFromType() was changed.

Breaking Changes

.. _upgrade-421-get_cookie:

get_cookie()

If there is a cookie with a prefixed name and a cookie with the same name without a prefix, the previous get_cookie() had the tricky behavior of returning the cookie without the prefix.

For example, when Config\Cookie::$prefix is prefix_, there are two cookies, test and prefix_test:

.. code-block:: php

$_COOKIES = [
    'test'        => 'Non CI Cookie',
    'prefix_test' => 'CI Cookie',
];

Previously, get_cookie() returns the following:

.. code-block:: php

get_cookie('test');        // returns "Non CI Cookie"
get_cookie('prefix_test'); // returns "CI Cookie"

Now the behavior has been fixed as a bug, and has been changed like the following.

.. code-block:: php

get_cookie('test');              // returns "CI Cookie"
get_cookie('prefix_test');       // returns null
get_cookie('test', false, null); // returns "Non CI Cookie"

If you depend on the previous behavior, you need to change your code.

.. note:: In the example above, if there is only one cookie prefix_test, the previous get_cookie('test') also returns "CI Cookie".

Breaking Enhancements

Project Files

Numerous files in the project space (root, app, public, writable) received updates. Due to these files being outside of the system scope they will not be changed without your intervention. There are some third-party CodeIgniter modules available to assist with merging changes to the project space: Explore on Packagist <https://packagist.org/explore/?query=codeigniter4%20updates>_.

.. note:: Except in very rare cases for bug fixes, no changes made to files for the project space will break your application. All changes noted here are optional until the next major version, and any mandatory changes will be covered in the sections above.

Content Changes

All Changes

This is a list of all files in the project space that received changes; many will be simple comments or formatting that have no effect on the runtime: