docs: require min PHP version 8.0

Author: kenjis

README.md

@@ -86,7 +86,7 @@ Made with [contrib.rocks](https://contrib.rocks).
 
 ## Server Requirements
 
-PHP version 7.4 or higher is required, with the following extensions installed:
+PHP version 8.0 or higher is required, with the following extensions installed:
 
 - [intl](http://php.net/manual/en/intl.requirements.php)
 - [mbstring](http://php.net/manual/en/mbstring.installation.php)

admin/framework/README.md

@@ -42,7 +42,7 @@ Please read the [*Contributing to CodeIgniter*](https://github.com/codeigniter4/
 
 ## Server Requirements
 
-PHP version 7.4 or higher is required, with the following extensions installed:
+PHP version 8.0 or higher is required, with the following extensions installed:
 
 - [intl](http://php.net/manual/en/intl.requirements.php)
 - [mbstring](http://php.net/manual/en/mbstring.installation.php)

admin/starter/README.md

@@ -50,7 +50,7 @@ Problems with it can be raised on our forum, or as issues in the main repository
 
 ## Server Requirements
 
-PHP version 7.4 or higher is required, with the following extensions installed:
+PHP version 8.0 or higher is required, with the following extensions installed:
 
 - [intl](http://php.net/manual/en/intl.requirements.php)
 - [mbstring](http://php.net/manual/en/mbstring.installation.php)

contributing/pull_request.md

@@ -136,7 +136,7 @@ See [Contribution CSS](./css.md).
 
 ### Compatibility
 
-CodeIgniter4 requires [PHP 7.4](https://php.net/releases/7_4_0.php).
+CodeIgniter4 requires [PHP 8.0](https://php.net/releases/8_0_0.php).
 
 ### Backwards Compatibility
 

user_guide_src/source/installation/upgrade_4xx.rst

@@ -41,7 +41,7 @@ Downloads
 Namespaces
 ==========
 
-- CI4 is built for PHP 7.4+, and everything in the framework is namespaced, except for the helpers.
+- CI4 is built for PHP 8.0+, and everything in the framework is namespaced, except for the helpers.
 
 Application Structure
 =====================

user_guide_src/source/intro/requirements.rst

@@ -2,7 +2,7 @@
 Server Requirements
 ###################
 
-`PHP <https://www.php.net/>`_ version 7.4 or newer is required, with the following PHP extensions are enabled:
+`PHP <https://www.php.net/>`_ version 8.0 or newer is required, with the following PHP extensions are enabled:
 
   - `intl <https://www.php.net/manual/en/intl.requirements.php>`_
   - `mbstring <https://www.php.net/manual/en/mbstring.requirements.php>`_