Install multiple PHP versions on Ubuntu with the ondrej PPA

Ubuntu ships one PHP version per release (8.3 on Ubuntu 24.04). The widely used ondrej/php PPA, maintained by a Debian PHP maintainer, provides every supported PHP version so you can run several side by side. Each version gets its own PHP-FPM service, so different sites can use different versions.

Before you start

• Ubuntu 22.04 or 24.04 with sudo access.
• A web server (Apache or Nginx) if you serve websites; see LEMP stack or LAMP stack.
• On AlmaLinux or Rocky use Remi instead: PHP from Remi. On cPanel use EasyApache 4.

Add the PPA

apt update && apt -y install software-properties-common
add-apt-repository -y ppa:ondrej/php
apt update

For Apache, also add ppa:ondrej/apache2 so Apache stays compatible with the PHP packages.

Install PHP versions

Install each version you need with FPM and common extensions, for example 8.2 and 8.4:

apt -y install php8.2-fpm php8.2-mysql php8.2-curl php8.2-gd php8.2-mbstring php8.2-xml php8.2-zip php8.2-intl

apt -y install php8.4-fpm php8.4-mysql php8.4-curl php8.4-gd php8.4-mbstring php8.4-xml php8.4-zip php8.4-intl

Each version runs as its own service, for example php8.2-fpm, with a socket at /run/php/php8.2-fpm.sock.

Choose the command-line default

update-alternatives --set php /usr/bin/php8.4
php -v

Or pick interactively with update-alternatives --config php. Composer and cron jobs use this default unless you call /usr/bin/php8.2 directly.

Assign a version per site

• Nginx: in the site's server block set fastcgi_pass unix:/run/php/php8.2-fpm.sock; and reload Nginx.
• Apache: enable proxy_fcgi and in the virtual host add:
  Copy

  <FilesMatch \.php$>
    SetHandler "proxy:unix:/run/php/php8.2-fpm.sock|fcgi://localhost"
  </FilesMatch>

Settings and hardening

• Edit each version separately: /etc/php/8.2/fpm/php.ini and pool files in /etc/php/8.2/fpm/pool.d/.
• Run each site's pool under its own Linux user for isolation.
• Remove versions you no longer use: apt purge 'php7.4*'.
• Updates arrive through normal apt upgrade.

Verify

systemctl status php8.2-fpm php8.4-fpm

Place a temporary phpinfo() file on each site and confirm the expected version, then delete it.

Troubleshooting

• Package not found: run apt update after adding the PPA; check your Ubuntu release is still supported by the PPA.
• 502 Bad Gateway: the socket path does not match the installed version.
• Extension missing in one version: extensions are per version; install php8.2-EXT for each.

Next steps

• Tune PHP-FPM pools
• Upgrade a site's PHP version
• Install Memcached