One Page Checkout and all OPC Extensions are php7 and php8 Compatible
PHP7.4 is recommended for all Joomla 3 and Virtuemart 3 implementations with up to date versions. Mysql 5.7 is recommended and Mysql 8.0 is supported. For Joomla 4 we suggest php8.1 and mysql5.7 or mariadb10.5 and later.