The TRDX file contains the report XML definition with specified schema version based on the used Telerik Reporting version.
Report that is created or modified with a newer version (creating report with the Standalone Designer) cannot be processed by the older version (Telerik Report Server). When you modify the report in Standalone designer of the newer version, the XML schema of the report will be updated. Designer of the older version is not able to read the updated schema and will show an error "Cannot read a document with the specified schema.." .
The same applies to the scenario between Report Server and the other machine which should preview the report in a report viewer. So, in order to successfully work with different versions of Telerik Reporting and Telerik Report Server, version C must be the same or higher than B, and B must be the same or higher than A.
For more specific suggestions/recommendation please specify the A, B, C versions with the actual ones.
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Feedback Portal
and vote to affect the priority of the items