We only officially support the latest stable branch of Joomla!. At the time of this writing it is Joomla! 3.9.
Our software should still run on Joomla! 3.8. That version are not actively supported by us or the Joomla! project anymore. We strongly advise you to run the latest available version of Joomla! for security reasons. Older versions of Joomla! have known major security issues which are being actively exploited to hack sites.
We only officially support using our software with PHP 5.6, 7.2, 7.3 or 7.4.
Our software should still run on PHP 7.0 and 7.1 but we are no longer testing our software with this PHP version or consider it a supported environment for our software.
We strongly advise you to run either of the two latest available version branches of PHP on a branch currently maintained by the PHP project for security and performance reasons. Older versions of PHP have known major security issues which are being actively exploited to hack sites and they have stopped receiving security updates, leaving you exposed to these issues. Moreover, they are slower, therefore consuming more server resources to perform the same tasks.
Kindly note that our policy is to officially support only the PHP versions which are not yet End Of Life per the official PHP project with a voluntarily extension of support for 6 to 9 months after they become End of Life. After that time we stop providing any support for these obsolete versions of PHP without any further notice. New version branches of PHP will be supported experimentally starting sometime during their Release Candidate phase and fully about 4 to 8 weeks after the first stable version of that branch is released.