In the coming release of Calem Enterprise R2021, the support of PHP 7.4 is included. Customers of on-premise implementation can download the release when it is available (planned for January 2021). The release source archive will have "php72" in it such as "CalemEnterprise_2021_ioncube.php72.tar.gz" here (customer account is required).
This blog walks through the upgrade process at high level. Customers can get in touch with Calem Support Team when needed. The discussion assumes that Ubuntu LTS 20.04 is used as the operating system.
Step 1. Ubuntu LTS 20.04
Assume that you have your VM (virtual machine) of Ubuntu LTS 20.04. Follow Calem Enterprise Installation Guide from here (customer account required) to set up Apache, MySQL and PHP for Ubuntu 20.04.
Step 2. Calem Setup
Use "Chapter 4 Installation Preparation" of Calem Installation Guide to set up the following items:
Both installation and database of current Calem Enterprise installation will need to be migrated for the new service. It is possible to reuse your current database without creating a new one for the upgrade. It is cleaner to create a new database for this discussion.
Follow the upgrade process of Calem Enterprise Installation Guide to deploy the source archive of Calem Enterprise R2021 for PHP 7.2 to the current installation in the new server. This step replaces the source code of current installation with the one for PHP 7.2.
Step 5. Web Installation
The final step is to run the web installation (see Calem Enterprise Installation Guide). Follow the steps in the Installation Guide to upgrade your current database to R2021.
You should be all set with the PHP 7.4 upgrade.