$ sudo update-alternatives --config php or $ sudo a2enmod php7.1(version)
//In ubunutu Default PHP 7.1 is set on your system and you need to switch to PHP 5.6 $ sudo a2dismod php7.1 $ sudo a2enmod php5.6 $ sudo service apache2 restart sudo update-alternatives --set php /usr/bin/php5.6
update-alternatives --set php /usr/bin/php7.4 update-alternatives --set phar /usr/bin/phar7.4 update-alternatives --set phar.phar /usr/bin/phar.phar7.4 update-alternatives --set phpize /usr/bin/phpize7.4 update-alternatives --set php-config /usr/bin/php-config7.4