In the last version we introduced a number of interactive features like report parameters, expandable regions, and dynamic sortings. Until version 20, using these in a web application was not possible as they result in a partial rerendering of the report or – for drilldown reports – trigger a brand new report. As the existing viewers didn't have a communication channel to a server control, this rerendering was impossible.
Enter the new HTML5 viewer. This viewer is designed to work in almost any web browser. It is optimized for mobile devices and supports interactivity. It requires ASP.NET on the server side but can use any operating system on the client.