I have to copy all reports from one SSRS server to another. I plan on doing this by going through each report and downloading the report definition file and then uploading t
For SQL Server Reporting Services 2008 R2 or later, Microsoft have a migration tool:
http://www.microsoft.com/en-us/download/details.aspx?id=29560
Reporting Services Migration Tool
A tool that migrates reports and other artifacts from one report server to another report server. It can also be used as a backup and restore tool for Reporting Services.
I haven't made personal use of this, and to be honest the description lists a few failings that the developers are 'working towards a solution' on, but it might help someone out.