I'm trying to upgrade from php 5 to 7 on a server hosting a symfony project. Actually the update from php 5 to 7 worked ;

php --version
PHP 7.2.29 (cli) (built: Mar 17 2020 11:58:47) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies
    with Zend OPcache v7.2.29, Copyright (c) 1999-2018, by Zend Technologies

but now on my server only "public" pages worked, I mean when I go a page that needs the ORM it returns a 500 internal error. The log server file gives me this output :

[2020-03-20 14:38:49] request.CRITICAL: Uncaught PHP Exception Symfony\Component\Validator\Exception\MappingException: "Extension DOM is required." at /var/www/myProject/vendor/symfony/symfony/src/Symfony/Component/Validator/Mapping/Loader/XmlFileLoader.php line 179 {"exception":"[object] (Symfony\\Component\\Validator\\Exception\\MappingException(code: 0): Extension DOM is required. at /var/www/myProject/vendor/symfony/symfony/src/Symfony/Component/Validator/Mapping/Loader/XmlFileLoader.php:179, RuntimeException(code: 0): Extension DOM is required. at /var/www/myProject/vendor/symfony/symfony/src/Symfony/Component/Config/Util/XmlUtils.php:45)"} []
[2020-03-20 14:38:50] security.INFO: No expression found; abstaining from voting. [] []
[2020-03-20 14:38:50] security.INFO: No expression found; abstaining from voting. [] []

So I googled the error and thus I did that :

sudo yum install php72-php-mbstring php72-php-xml php72-php-xmlrpc

Then :

php -d memory_limit=-1 composer.phar update --no-cache
php -d memory_limit=-1  app/console cache:clear --env=prod
sudo systemctl restart httpd.service

And I still got this error...

EDIT : The cli version is PHP 7.2.29 which uses /etc/opt/remi/php72/php.ini file and the server PHP (showed by phpinfo(); function ) show PHP version 7.2.28 which uses /etc/php.ini file. I think I have to investigate with some apache config.