PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian
PHP 8.4 brings several new features, security improvements, and performance improvements with healthy amounts of feature deprecations and removals.
This guide explains how to install PHP 8.4 or upgrade to PHP 8.4 on Ubuntu, Debian, or their derivatives. Although it is possible to compile PHP from source, installing it from an APT repository as explained below is often faster and more secure because these repositories will provide the latest bug fixes and security updates in the future.
PHP 8.4 is not available in current Debian and Ubuntu software repositories. This guide uses the repositories maintained by Ondřej Surý. Ondrej's PHP repositories have been the de-facto repositories for PHP on Ubuntu, Debian, and their derivatives for several years.
Potential Backward Compatibility Impact in PHP 8.4
PHP 8.4 brings several new features such as property hooks, asymmetric visibility, improvements in DOM, Curl, PCRE extensions, and more.
However, PHP 8.4 also deprecates some PHP functionality and removes four PHP extensions from PHP core to PECL. This can affect existing PHP applications to emit additional PHP notices/warnings, or fail in certain conditions.
Some of the notable changes that are likely to affect existing applications include:
- Implicitly nullable parameter declarations deprecated
E_STRICTconstant deprecated- Extensions moved from PHP core to PECL: Pspell, IMAP, OCI8, and PDO_OCI.
When a PHP extension is moved from PHP core to PECL, the extension will follow its own release cycle. The repositories used in the guide will provide updates for them if the PECL project for that extension releases updates. However, this also means the PECL extension can (and often does) fall behind on maintenance.
Before continuing, make sure to backup the system. This guide installs PHP 8.4 side-by-side along any existing PHP installations, which offers an easy way to switch back to the other PHP installation if necessary.
1. List existing PHP packages
This step only applies when upgrading an existing PHP setup. The following command lists all installed PHP packages with the text php in its name, shows it on screen, and writes it to a file called packages.txt. This file comes in handy at a later step when installing the PHP 8.4 packages, to ensure the same list of PHP 8.4 versions of the extensions are installed.
dpkg -l | grep php | tee packages.txt2. Add ondrej/php PPA/DPA
Because PHP 8.4 packages are not available in any of the current Debian or Ubuntu software repositories, the PHP packages must come from another repo.
Ondřej Surý maintains a package archive that contains compiled binaries of all current PHP versions, for Ubuntu and Debian. It also ships several PECL extensions including PECL extensions for PHP core extensions unbundled in PHP 8.4.
Once this repository is added, the initial installation and updates can be done with the standard apt commands.
Ubuntu PPA
sudo LC_ALL=C.UTF-8 add-apt-repository ppa:ondrej/php # Press enter to confirm.
sudo apt updateDebian DPA
sudo apt-get update
sudo apt-get -y install lsb-release ca-certificates curl apt-transport-https
sudo curl -sSLo /tmp/debsuryorg-archive-keyring.deb https://packages.sury.org/debsuryorg-archive-keyring.deb
sudo dpkg -i /tmp/debsuryorg-archive-keyring.deb
sudo sh -c 'echo "deb [signed-by=/usr/share/keyrings/deb.sury.org-php.gpg] https://packages.sury.org/php/ $(lsb_release -sc) main" > /etc/apt/sources.list.d/php.list'
sudo apt-get update3. Install PHP 8.4 Server API packages
In the Ondrej's PPA and DPA, PHP 8.4 packages follow the php8.1-NAME pattern. PECL and shared PHP extensions also follow the same pattern.
Before installing PHP extensions, make sure to install one of the following PHP Server API (SAPI) packages:
Install PHP-CLI only
To install PHP CLI, install the php8.1-cli package, along with the extensions desired.
sudo apt install php8.4-cliPHP-CLI and PHP as an Apache module
To install PHP CLI and PHP 8.4 as an Apache module, install the libapache2-mod-php8.4 package:
sudo apt install php8.4-cli libapache2-mod-php8.4Unless the PHP application requires PHP to be installed as an Apache module, consider installing PHP-FPM instead.
PHP CLI and PHP-FPM (recommended)
It is recommended to install PHP-FPM to integrate PHP with web-servers such as Apache, Nginx, and Caddy.
sudo apt install php8.4-cli php8.4-fpmThis installs the php8.4-fpm service and automatically enables it. See the FPM web-server integration section for the additional steps required later.
5. Check Installation
For a quick check of the PHP installation, run the following:
php -vIt should show the PHP version, build time, and more information:
If the PHP-FPM service is installed, its status can be checked as follows:
sudo systemctl status php8.4-fpmIf the PHP-FPM server is running successfully, it should show an output similar to below:
4. Install PHP Extensions
All of the shared PHP extensions and PECL extensions follow the php8.4-EXTNAME pattern, where extname is the name of the extension.
When upgrading an existing system, refer to the packages.txt file created in the first step to check the existing PHP 8.3 or older PHP extensions.
To install a PHP extension, use the apt install command with the PHP extension name with the php-8.4- prefix. For example, the gd extension is installed with the php8.4-gd package:
sudo apt install php8.4-gdThe following command installs a set of most common PHP extensions required by a majority of PHP libraries and frameworks:
sudo apt install php8.4-common php8.4-{bcmath,bz2,curl,gd,gmp,intl,mbstring,opcache,readline,xml,zip}To search for additional PHP extensions, use the apt search command:
apt search php8.4Development Tools
Development tooling such as Xdebug and code coverage tools can also be installed following the same package naming convention.
This step is not recommended on production servers.
Xdebug
sudo apt install php8.4-xdebugPCOV
sudo apt install php8.4-xdebug5. Web Server Integration
Depending on the server API installed in step 3, web server integration might require additional configuration for the PHP 8.4 upgrade to take effect.
PHP-FPM
When using PHP-FPM (by installing the php8.4-fpm package), the web server needs to be reconfigured to communicate with the PHP 8.4 FPM server over the updated the socket path.
Apache: This configuration change is made easy by switching on the PHP 8.4 configuration file:
sudo a2enconf php8.4-fpmNginx: Update the fastcgi_pass directive from the old PHP FPM socket path to the new PHP 8.4 path:
- fastcgi_pass unix:/run/php/php8.3-fpm.sock;
+ fastcgi_pass unix:/run/php/php8.4-fpm.sock; See Nginx documentation for more information
Caddy Server: Update the reverse_proxy directive to use the new PHP 8.4 FPM server socket path:
- reverse_proxy @phpFiles unix//run/php/php8.3-fpm.sock
+ reverse_proxy @phpFiles unix//run/php/php8.4-fpm.sockSee How to use Caddy Server with PHP for more configuration details.
PHP as an Apache module
If PHP is installed as an Apache module, the following command disables the previous PHP module (8.3 in this example) and enables the new PHP version:
sudo a2dismod php8.3 # Change to the current PHP version
sudo a2enmod php8.4Migrate Configuration
The configuration files for the new PHP setup will be in the /etc/php/8.4 directory. The existing PHP installations are likely installed in the /etc/php/VERSION directories.
If desired, the configuration can be copied from older PHP versions. Copying over the existing files is not configured. Instead, consider checking the differences between two php.ini files and updating the PHP 8.4 php.ini files.
For example, the following command compares the PHP 8.4 CLI php.ini against PHP 8.4s:
diff /etc/php/8.3/cli/php.ini /etc/php/8.4/cli/php.iniWhen using PHP-FPM, make sure to update the /etc/php/8.4/fpm/pool.d/www.conf file to match the older PHP-FPM runner pool configuration.
Purge Old PHP Versions
After confirming that the new PHP CLI (and optionally the web server integrations) work correctly, the packages and services of the old PHP versions can be removed if they are no longer necessary.
sudo apt purge '^php8.3.*'The example above shows an apt purge command that wildcard matches all PHP 8.3 packages.
Running PHP 8.4 alongside other PHP versions
If desired, PHP 8.4 installation mentioned in the steps above can co-exist with other PHP versions.
When installing PHP 8.4 CLI, it will be installed at /usr/bin/php8.4. Other PHP versions will be installed at the same location with the version name suffix (for example, PHP 8.3 at /usr/bin/php8.3). It is possible to invoke other PHP CLI versions directly by calling this path.
The default php command name will be symlinked to the latest PHP version by default. However, using the update-alternatives command, this can be changed to any other PHP version:
sudo update-alternatives --config phpThis opens an interactive interface to select the alternative PHP binary path that php points to:
There are 2 choices for the alternative php (providing /usr/bin/php).
Selection Path Priority Status
------------------------------------------------------------
* 0 /usr/bin/php8.4 84 auto mode
1 /usr/bin/php8.3 83 manual mode
2 /usr/bin/php8.4 84 manual modeTo set the path without the interactive prompt:
update-alternatives --set php /usr/bin/php8.4
