As we already explained the Classic version of the Telerik Web Forms components is discontinued for almost a decade (since 2009).
We do recommend, but we are not forcing anyone to upgrade to Telerik UI for ASP.NET AJAX, because the Classic suite does not expose any built-in time errors and limitations and also the documentation is available in the installations of the Classic controls. That's why everyone who still uses the Classic controls has an option to continue using them.
If someone wants to receive an offline version of the documentation for a specific classic component, he/she can do that by opening a support ticket from the support ticketing system
and specifying the name and version of the used classic component.