To find the system requirements for previous feature releases, such as 4D v19 R6,
go to the following link: https://us.4d.com/resources/feature-release
When you are on the Feature Release tab, scroll down to Compatibility > click See all
Here you can download the System Requirements for all the different feature releases of 4D.
Similarly, the 4D v19LTS tab will have the System Requirements under Compatibility for the dot releases.