- Plesk for Linux
PHP 5.6 is missing from Plesk Installer.
Is it possible to install PHP 5.x in Plesk on Debian 9 and Ubuntu 18.04 via Plesk Installer?
By default, Debian 9 and Ubuntu 18.04 support only those versions of PHP that support OpenSSL 1.1, and that are PHP 7.x and newer. As Debian 9 and Ubuntu 18.04 do not support such configuration out of the box, it is not possible to install PHP 5.x via Plesk Installer.
It is possible to add PHP 5.x for Debian 9 or Ubuntu 18.04 as a custom PHP according to the article.