I've been tasked to deploying reports to a client. however the dev was done on sql2012, but the client has sql2008 r2 installed. is there a way to "downgrade" the reports and shared data sets from 2012 to 2008r2?
Those version numbers sound the wrong way round to me. If the version problem is your dev environment vs their Reporting version, I would expect the 'expected' version number to be higher than the 'found' version number. Have you tried just confirming that their Reporting system works at all? Does the Report Manager function OK? Maybe the version difference is internal to their reporting installation and nothing to do with your dev version.