Where is the user manual for TitanFTP NextGen?

Where is the user manual for TitanFTP NextGen?

Why are there no current manuals available on the website?
The one for TitanFTP is dated 2018.
This link below is supposed to be for the latest version of Cornerstone but you get a "500 internal error" when trying to access it.
I would like to understand more about the clustering technology and caveats.
Please provide us with more documentation that is up-to-date.