Default values, that are shown in PHP-Selector web interface, are taken from '/opt/alt/phpXX/usr/bin/php -i' runtime values, if directive is not there, it will use 'default' value that was set in php.conf . So, if you wish to change default value of any option for "alternative" php version, please modify /opt/alt/phpXX/etc/php.ini files (where XX = 55, 54, 53, etc according to php version).