If you are still running your website or application on PHP 7.4, it's the right time to upgrade. PHP 7.4 reached its end of life, meaning it no longer receives any bug fixes or security patches — which can be risky for your website. PHP 8.1 is faster, more secure, and comes with several modern features that make coding easier.
In this simple guide, you’ll learn exactly what changes in PHP 8.1, how to upgrade your existing PHP 7.4 project step by step, and what you should check before switching your live website to PHP 8.1.
- PHP 7.4
- PHP 8.1
- Upgrade Guide
Why Should You Upgrade from PHP 7.4 to PHP 8.1?
Here are the main reasons why upgrading makes sense:
- PHP 7.4 is outdated — no security support.
- Performance boost — PHP 8+ can be up to 50% faster.
- Cleaner code thanks to new syntax features.
- Better compatibility with modern frameworks like Laravel, Symfony, and WordPress.
- Improved error handling and strict type validation.
Upgrading makes your project future-proof and more stable.
Step-by-Step Checklist to Upgrade from PHP 7.4 to PHP 8.1
1. Check Your Current PHP Version
php -v
Make sure you know what version your server is currently running before you start.
2. Update All Composer Packages
Most outdated packages can break your project when you switch to PHP 8.1. Update them first:
composer update
If any package shows “PHP 7 only”, replace it with a modern alternative.
3. Scan Your Code for Compatibility Issues
Tools like PHPStan help you detect warnings before upgrading:
composer require --dev phpstan/phpstan vendor/bin/phpstan analyse
Major Differences Between PHP 7.4 and PHP 8.1
PHP 8 comes with new rules that may break older code. Here are the main changes you need to fix:
1. Old Functions Removed
create_function()removedeach()removedimplode()old argument order removed
If your project uses these, you must rewrite them.
2. Warnings Become Errors
Many small warnings in PHP 7 now crash your code in PHP 8. For example:
$value = @$arr['name']; // risky in PHP 8
Use this instead:
$value = $arr['name'] ?? null;
3. Stricter Argument Types
PHP 8 checks your variable types more strictly. For example:
strpos([], "a");
This will throw a fatal error. You need to convert values properly:
strpos((string)$data, "a");
Exciting New Features in PHP 8.1
Once you upgrade, you get access to many modern coding features.
Enums
enum Status { Active, Pending, Disabled }
Readonly Properties
class User {
public readonly string $email;
}
First-class Callables
$fn = strlen(...);
These features make your code cleaner, faster, and easier to maintain.
Test Your Project Before Switching Server to PHP 8.1
Follow this small testing process to avoid breaking your live website:
- Clone your current project
- Switch your local environment to PHP 8.1
- Run all pages, forms, and features
- Fix any warnings or errors
- Test APIs if your app uses them
- Check error logs carefully
How to Upgrade PHP Version on Live Server
1. Take a Full Backup
Always back up your database and files before making major changes.
2. Test on Staging Server
Never upgrade directly on your main website.
3. Change PHP Version in cPanel
Select PHP Version → 8.1 → Apply
4. Clear All Cache
php artisan cache:clear php artisan config:clear
5. Test Everything Again
Make sure all pages load and no errors appear.
Common Errors After Switching to PHP 8.1 (and How to Fix Them)
1. "Attempt to read property on null"
Fix using the safe navigation operator:
$user?->name;
2. "Trying to access array offset on value of type string"
Check variable type before accessing it.
3. Composer issues
Update your composer version:
composer self-update