Magento 2.4.0 is require PHP 7.4, Elasticsearch 7.6.x and MySQL 8.0.   First check with your server: => Make sure your server is configured to work with PHP 7.4. Magento 2.4.0 officially support only PHP 7.4. Though you can install Magento 2.4.0 with PHP 7.3 but it is not tested. So it is recommended to use PHP 7.4 with Magento 2.4.0. => Make sure your composer is pointing to correct PHP version 7.4. => Make sure your server has installed and configured Elasticsearch 7.6.x. Magento 2.4.0 does not support MySQL as a catalog search engine. => Take a code and database backup.   Follow below step to upgrade Magento version from 2.3.X to 2.4.0 Step 1: If you are directly performing the upgrade on your live site then first put…