SQL Server 2016 Report Designer always upgrades to 2016 RDL schema
Update (7/25/16): You should be fine with older versions of Report Server and SSMS 2016/Visual Studio 2015/SSDT, if you do these three things: Set the appropriate compatibility level for deployment (TargetServerVersion) in the report project properties. Build the report project before deploying (this may also catch some kinds of errors). … Continue reading →