This article explains the manual changes required when upgrading to Telerik Reporting Q3 2014 (220.127.116.117).
The viewer is build with Telerik UI Controls for WPF 2014.3.1021.40. If you are using a newer version consider adding binding redirects. For more information see: How to Add report viewer to a WPF .NET Framework project
The viewer is build with Telerik UI Controls for Silverlight 2014.3.1021.1050.
TRDX files created by the Standalone Report Designer contain XML version http://schemas.telerik.com/reporting/2012/3.7