Yes, multiple PHP versions can be run on a single server, which can be implemented in conjunction with Nginx or Apache through PHP-FPM; 1. Install multiple PHP versions of FPM packages (such as php7.4-fpm, php8.3-fpm); 2. Ensure that each FPM service is running normally; 3. Configure server blocks for different sites in Nginx, point to the corresponding PHP-FPM socket through fastcgi_pass; 4. If using Apache, enable mod_proxy_fcgi module and specify FPM sockets through SetHandler in the virtual host; 5. You can switch the default version of CLI through update-alternatives or directly call a specific version; 6. Note that each PHP version needs to install extensions independently, manage OPcache, log files and security updates; this method can effectively and securely realize the coexistence of multiple PHP versions without containers, and is suitable for production environments.

Running multiple PHP versions on a single server isn't just possible—it's common. Whether you're maintaining legacy apps that require PHP 7.4 while developing new projects on PHP 8.3, or hosting multiple clients with different needs, managing multiple PHP environments efficiently is key. Here's how to do it smoothly without spinning up extra servers or containers.

Why Run Multiple PHP Versions?

Not all applications evolve at the same pace. A WordPress site might still depend on an old plugin incompatible with PHP 8, while your Laravel API uses the latest features from PHP 8.2 . Instead of forcing upgrades (which can break things), you can serve different sites with different PHP versions—on the same machine.

The good news? Modern web servers and PHP handlers make this manageable.

Use PHP-FPM with Nginx (or Apache)

The most flexible and widely used approach is pairing Nginx (or Apache) with PHP-FPM (FastCGI Process Manager). Each PHP version runs its own FPM pool, and your web server routes requests to the appropriate one based on the site.

Step-by-step setup (Ubuntu/Debian):

1. Install multiple PHP versions

   

    sudo apt install php7.4-fpm php8.0-fpm php8.1-fpm php8.2-fpm php8.3-fpm

   Each installs its own FPM service: php7.4-fpm , php8.3-fpm , etc.

2. Check FPM services

    sudo systemctl status php7.4-fpm
   sudo systemctl status php8.3-fpm

   They can all run simultaneously without conflict.

3. Configure Nginx server blocks

   For a site needing PHP 7.4:

    server {
       listen 80;
       server_name site-old.com;
       root /var/www/old-site;
   
       index index.php;
   
       location ~ \.php$ {
           include snippets/fastcgi-php.conf;
           fastcgi_pass unix:/run/php/php7.4-fpm.sock;
       }
   }

   For a modern app on PHP 8.3:

    server {
       listen 80;
       server_name site-new.com;
       root /var/www/new-app;
   
       index index.php;
   
       location ~ \.php$ {
           include snippets/fastcgi-php.conf;
           fastcgi_pass unix:/run/php/php8.3-fpm.sock;
       }
   }

4. Reload Nginx

    sudo nginx -t && sudo systemctl reload nginx

Each site now runs on its designed PHP version—no interference.

Managing Apache? Use mod_proxy_fcgi

If you're on Apache, mod_proxy_fcgi lets you proxy PHP requests to different FPM sockets.

Enable required modules:

 sudo a2enmod proxy_fcgi

Then in your virtual host:

 <VirtualHost *:80>
    ServerName legacy-site.com
    DocumentRoot /var/www/legacy

    <FilesMatch \.php$>
        SetHandler "proxy:unix:/run/php/php7.4-fpm.sock|fcgi://localhost"
    </FilesMatch>
</VirtualHost>

Same principle: route .php files to the right FPM socket.

Switch CLI Version (Optional)

The system can only have one default php command. But you can switch it easily:

 sudo update-alternatives --config php

This lets you pick which version runs when you type php in the terminal. Useful for Composer or artisan commands.

Alternatively, call specific versions directly:

 php8.3 artisan migrate
php7.4 composer install

Bonus: Tools to Simplify Management

• phpbrew – Great for developers testing versions locally, less ideal for production.
• Docker – Ultimate isolation, but adds complexity. Overkill if you just need version-per-site.
• Plesk/cPanel – Some hosting control panels support multi-PHP out of the box.

But for most production servers, native PHP-FPM Nginx/Apache is lightweight and reliable.

Watch Out for These Gotchas

• Extensions must be installed per version : mysqli on PHP 8.3 doesn't mean it's on 7.4. Install them separately.
• OPcache is per-FPM pool : Each version has its own cache. Clear carefully.
• Log files are separate : Check /var/log/php7.4-fpm.log vs /var/log/php8.3-fpm.log .
• Security updates : Don't forget older versions. Even if it's legacy, patch it.

Basically, you're not stuck with one PHP version per server. With PHP-FPM and a smart web server config, you can juggle versions like a pro-safely, efficiently, and without containers. It's not flashy, but it works.

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