when deploying SSRS report from ax 2012 R2 to R3 i got following error :
and i did some search for this error , here is the solution :
1. http://mafsarkhan.blogspot.com/2014/04/upgrade-ssrs-reports-from-dynamics-ax.html
2. https://technet.microsoft.com/en-us/library/hh389762.aspx
so i did export all the R2 reports in one project, replace all the version from 6.2.0.0 to 6.3.0.0 with notepad++, and reimport again, and done :d