Hi Nicholas,
How did you upgrade your CR runtimes?
What procedure did you follow.?
When you say CR 2011 runtimes, exactly which runtime package did you install.
The reason being, CR 2011 does not have (install) any SDK. See below DOC (its the same for CR 2011 and CR 2013).
How do you spell confusion; CR for VS, Crystal 2011, BI 4.x and the .NET SDKs
So, installing CR 2011 designer does not make a difference.
The equivalent version of CR that has the .NET SDK is the SAP Crystal Reports, developer version for Microsoft Visual Studio. You can download this version from here:
http://scn.sap.com/docs/DOC-7824
To upgrade the app to new CR version, you would need to recompile the app with newer CR assembly references.
Thanks,
Bhushan