Sitecore only provides limited documentation and support for Technical preview releases (RTT) of Sitecore products.
Sitecore provides support for technical preview releases with the following limitations:
As soon as the status of the product is changed from a technical preview release to a regular release, Sitecore will provide its normal level of support. This is expected to happen after Sitecore has released one or more updates for the technical preview release and when a complete set of documentation is available.