All our extensions support Joomla 4, and we continually test with the latest releases.
Our extensions also work in current versions of Joomla 3, with a minimum of Joomla 3.7. We plan to support Joomla 3 until at least one year after its end of life, i.e. until at least August 2024.
We recommend that you keep your site up to date with the latest version of Joomla. From time to time security issues emerge, and sites that are not updated may be attacked once details of the problem are published. In general you can assume that our extensions work on new releases of Joomla, but if your site is critical to your business you should have a test site where you can test upgrades before implementing them in your live site.
There's a useful table of Joomla versions and support dates at http://docs.joomla.org/Joomla!_CMS_versions
Our extensions work with all versions of PHP 7 and 8, including PHP 8.2.
There's a useful table of PHP versions and support dates at https://www.php.net/supported-versions. You should be using at least PHP 8.0.
Our extensions run with MySql and MariaDB. We do not test on SQL Server or PostgreSQL, and we don't allow our extensions to install on them.
Joomla 4 has dropped support for SQL Server, and we see no reason for Joomla to continue support for PostgreSQL.