Codeigniter 4 not workin PHP 8

I downloade development version from github, but not show this error for php on xampp 8.0.0

Code:

Deprecated: Required parameter $userAgent follows optional parameter $body in /opt/lampp/htdocs/hu/of/system/HTTP/IncomingRequest.php on line 131

Fatal error: Uncaught ErrorException: Cannot modify header information - headers already sent by (output started at /opt/lampp/htdocs/of/ofi/app/Config/Events.php:35) in /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php:137 Stack trace: #0 [internal function]: CodeIgniter\Debug\Exceptions->errorHandler(2, 'Cannot modify h...', '/opt/lampp/htdo...', 137) #1 /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php(137): header('HTTP/1.1 500 In...', true, 500) #2 [internal function]: CodeIgniter\Debug\Exceptions->exceptionHandler(Object(ErrorException)) #3 {main} thrown in /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php on line 137

Fatal error: Uncaught ErrorException: Cannot modify header information - headers already sent by (output started at /opt/lampp/htdocs/of/ofi/app/Config/Events.php:35) in /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php:137 Stack trace: #0 [internal function]: CodeIgniter\Debug\Exceptions->errorHandler(2, 'Cannot modify h...', '/opt/lampp/htdo...', 137) #1 /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php(137): header('HTTP/1.1 500 In...', true, 500) #2 /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php(197): CodeIgniter\Debug\Exceptions->exceptionHandler(Object(ErrorException)) #3 [internal function]: CodeIgniter\Debug\Exceptions->shutdownHandler() #4 {main} thrown in /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php on line 137

Use XAMPP 8.0.0
Fedora 33 x86_64
Codeigniter 4 from github

I downloade development version from github, but not show this error for php on xampp 8.0.0

Code:

Deprecated: Required parameter $userAgent follows optional parameter $body in /opt/lampp/htdocs/hu/of/system/HTTP/IncomingRequest.php on line 131

Fatal error: Uncaught ErrorException: Cannot modify header information - headers already sent by (output started at /opt/lampp/htdocs/of/ofi/app/Config/Events.php:35) in /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php:137 Stack trace: #0 [internal function]: CodeIgniter\Debug\Exceptions->errorHandler(2, 'Cannot modify h...', '/opt/lampp/htdo...', 137) #1 /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php(137): header('HTTP/1.1 500 In...', true, 500) #2 [internal function]: CodeIgniter\Debug\Exceptions->exceptionHandler(Object(ErrorException)) #3 {main} thrown in /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php on line 137

Fatal error: Uncaught ErrorException: Cannot modify header information - headers already sent by (output started at /opt/lampp/htdocs/of/ofi/app/Config/Events.php:35) in /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php:137 Stack trace: #0 [internal function]: CodeIgniter\Debug\Exceptions->errorHandler(2, 'Cannot modify h...', '/opt/lampp/htdo...', 137) #1 /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php(137): header('HTTP/1.1 500 In...', true, 500) #2 /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php(197): CodeIgniter\Debug\Exceptions->exceptionHandler(Object(ErrorException)) #3 [internal function]: CodeIgniter\Debug\Exceptions->shutdownHandler() #4 {main} thrown in /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php on line 137

Use XAMPP 8.0.0
Fedora 33 x86_64
Codeigniter 4 from github

Replace in this line

Code:

UserAgent $userAgent

with:

Code:

UserAgent $userAgent = null

Also, I saw a similar problem Route/RouteCollection.php file. If it is not corrected yet, replace the line

Code:

public function match(array $verbs = [], string $from, $to, array $options = null): RouteCollectionInterface

with:

Code:

public function match(array $verbs = [], string $from = null, $to = null, array $options = null): RouteCollectionInterface

Make these corrections on the system files directly, when you upgrde in the future these lines would be already fixed.

I downloade development version from github, but not show this error for php on xampp 8.0.0

Code:

Deprecated: Required parameter $userAgent follows optional parameter $body in /opt/lampp/htdocs/hu/of/system/HTTP/IncomingRequest.php on line 131

Fatal error: Uncaught ErrorException: Cannot modify header information - headers already sent by (output started at /opt/lampp/htdocs/of/ofi/app/Config/Events.php:35) in /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php:137 Stack trace: #0 [internal function]: CodeIgniter\Debug\Exceptions->errorHandler(2, 'Cannot modify h...', '/opt/lampp/htdo...', 137) #1 /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php(137): header('HTTP/1.1 500 In...', true, 500) #2 [internal function]: CodeIgniter\Debug\Exceptions->exceptionHandler(Object(ErrorException)) #3 {main} thrown in /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php on line 137

Fatal error: Uncaught ErrorException: Cannot modify header information - headers already sent by (output started at /opt/lampp/htdocs/of/ofi/app/Config/Events.php:35) in /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php:137 Stack trace: #0 [internal function]: CodeIgniter\Debug\Exceptions->errorHandler(2, 'Cannot modify h...', '/opt/lampp/htdo...', 137) #1 /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php(137): header('HTTP/1.1 500 In...', true, 500) #2 /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php(197): CodeIgniter\Debug\Exceptions->exceptionHandler(Object(ErrorException)) #3 [internal function]: CodeIgniter\Debug\Exceptions->shutdownHandler() #4 {main} thrown in /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php on line 137

Use XAMPP 8.0.0
Fedora 33 x86_64
Codeigniter 4 from github

Replace in this line

Code:

UserAgent $userAgent

with:

Code:

UserAgent $userAgent = null

Also, I saw a similar problem Route/RouteCollection.php file. If it is not corrected yet, replace the line

Code:

public function match(array $verbs = [], string $from, $to, array $options = null): RouteCollectionInterface

with:

Code:

public function match(array $verbs = [], string $from = null, $to = null, array $options = null): RouteCollectionInterface

Make these corrections on the system files directly, when you upgrde in the future these lines would be already fixed.

It's work, but have some errors minors, in pagers, thanks, i use this solution for wait the new version compatible wtih CI4 with PHP 8

I downloade development version from github, but not show this error for php on xampp 8.0.0

Code:

Deprecated: Required parameter $userAgent follows optional parameter $body in /opt/lampp/htdocs/hu/of/system/HTTP/IncomingRequest.php on line 131

Fatal error: Uncaught ErrorException: Cannot modify header information - headers already sent by (output started at /opt/lampp/htdocs/of/ofi/app/Config/Events.php:35) in /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php:137 Stack trace: #0 [internal function]: CodeIgniter\Debug\Exceptions->errorHandler(2, 'Cannot modify h...', '/opt/lampp/htdo...', 137) #1 /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php(137): header('HTTP/1.1 500 In...', true, 500) #2 [internal function]: CodeIgniter\Debug\Exceptions->exceptionHandler(Object(ErrorException)) #3 {main} thrown in /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php on line 137

Fatal error: Uncaught ErrorException: Cannot modify header information - headers already sent by (output started at /opt/lampp/htdocs/of/ofi/app/Config/Events.php:35) in /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php:137 Stack trace: #0 [internal function]: CodeIgniter\Debug\Exceptions->errorHandler(2, 'Cannot modify h...', '/opt/lampp/htdo...', 137) #1 /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php(137): header('HTTP/1.1 500 In...', true, 500) #2 /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php(197): CodeIgniter\Debug\Exceptions->exceptionHandler(Object(ErrorException)) #3 [internal function]: CodeIgniter\Debug\Exceptions->shutdownHandler() #4 {main} thrown in /opt/lampp/htdocs/of/ofi/system/Debug/Exceptions.php on line 137

Use XAMPP 8.0.0
Fedora 33 x86_64
Codeigniter 4 from github

Replace in this line

Code:

UserAgent $userAgent

with:

Code:

UserAgent $userAgent = null

Also, I saw a similar problem Route/RouteCollection.php file. If it is not corrected yet, replace the line

Code:

public function match(array $verbs = [], string $from, $to, array $options = null): RouteCollectionInterface

with:

Code:

public function match(array $verbs = [], string $from = null, $to = null, array $options = null): RouteCollectionInterface

Make these corrections on the system files directly, when you upgrde in the future these lines would be already fixed.

After I did these changes Now I'm getting this error when I access my public folder using "http://localhost/ci4project/public/". 
 404 - File Not Found

Controller method is not found: index

Means I'm unable to access the default codeigniter page which used to come while accessing public folder. Kindly help

It seems your CI4 is not the latest.
See https://github.com/codeigniter4/CodeIgni...t.php#L131

How do you download the latest develop branch?

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

If you want to use PHP 8 in earnest you should use the latest version of the 4.1 branch from the repo.

@McGatner,

I have a DigitalOcean VPS with Ubuntu 20.04 installed and “sudo apt update && sudo apt upgrade” installed PHP 8.01 much to my surprise! Fortunately the small CodeIgniter 4 applications are working OK.

Please supply a link where I can download CI 4.1. I have searched and wondering if the latest GitHub download is version 4.1

Edit:
Found the GitHub Down Clone link:

git clone https://github.com/codeigniter4/CodeIgniter4.git

@McGatner,

I have a DigitalOcean VPS with Ubuntu 20.04 installed and “sudo apt update && sudo apt upgrade” installed PHP 8.01 much to my surprise! Fortunately the small CodeIgniter 4 applications are working OK.

Please supply a link where I can download CI 4.1. I have searched and wondering if the latest GitHub download is version 4.1

Edit:
Found the GitHub Down Clone link:

git clone https://github.com/codeigniter4/CodeIgniter4.git

Hi, I have it using with laragon and with php7.2, it's going very well. Although I recommend if you work locally check one of my tools to work in a simple way.
use this: https://github.com/juanma386/desplegar
required install ubuntu in the windows and composer.

[Image: https://i.ibb.co/9t33pTc/hexomecloud.jpg]

Please supply a link where I can download CI 4.1. I have searched and wondering if the latest GitHub download is version 4.1

Edit:
Found the GitHub Down Clone link:

git clone https://github.com/codeigniter4/CodeIgniter4.git

It is `develop` branch.

You can switch to `4.1`.

cd CodeIgniter4.1/
git checkout 4.1

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