PHP Version Switching in DirectAdmin

DirectAdmin supports multiple simultaneous PHP versions via CustomBuild 2.0. Each domain can run a different PHP version: useful when hosting a mix of legacy and modern applications.

Installing PHP versions (server admin)

PHP versions are installed via CustomBuild on the server via SSH:

cd /usr/local/directadmin/custombuild

# See current PHP configuration
./build options | grep php

# Set PHP version slots (up to php4)
./build set php1_release 8.3
./build set php2_release 8.2
./build set php3_release 8.1
./build set php4_release 7.4   # legacy only if needed

# Set PHP mode (php-fpm recommended)
./build set php1_mode php-fpm
./build set php2_mode php-fpm

# Build and install
./build php n     # n = number of PHP versions configured
./build rewrite_confs

This takes 10-20 minutes per version. The server stays online during the build.

Switching PHP per domain (user level)

Once multiple versions are installed, users can switch PHP version for each domain:

Log into DirectAdmin as the user.

Go to Extra Features → PHP Version Selector.

Select the domain from the dropdown.

Choose the PHP version from the list of installed versions.

Click Save.

Changes take effect immediately: no restart needed.

Checking the active PHP version

From the domain’s document root via SSH:

php -v

# Or create a phpinfo file temporarily
echo "<?php phpinfo();" > /home/username/public_html/info.php
# Visit https://yourdomain.com/info.php
# Delete it afterwards
rm /home/username/public_html/info.php

Customizing PHP settings per domain

DirectAdmin allows custom php.ini values per domain via .htaccess:

# In .htaccess (PHP-FPM mode)
php_value memory_limit 512M
php_value upload_max_filesize 64M
php_value post_max_size 64M
php_value max_execution_time 300

Or through the user panel: Extra Features → PHP Configuration (if enabled).

Verifying PHP-FPM is running

# Check PHP-FPM pools
ps aux | grep php-fpm

# Check which PHP-FPM version is running for a user
ls /var/www/php-fpm/username/

PHP 8.2+ is significantly faster than 7.4 and 8.0. New WordPress sites should default to 8.2 or 8.3. Only use older versions for legacy code that hasn't been updated.