Svrl - 2021-07-28

Dear developer and community,
I would like to ask for little help to my questions below:
Is there any proper documentation or guide available for this application?
I would like to ask also for more information about environment, as which version of PhP or what next is also important to assume please?
* Is your application free to use? According to the used jpgraph license it is not for commercial use, am I wrong?

Application is also throwing same error, either on php 5.6 or 7.3:
Fatal error: Call to undefined function import_request_variables() in, which is function (import_request_variables) nowhere to be found inside whole project besides that call.

Thank you and have a nice day :).