Should I downgrade my software

Hello, I recently downloaded the MP32 core from SLS and I was having issues using it in Quartus 11.1. It did not appear in the QSYS library until I added a new component and after wards it disappeared again. However I used the core when it appeared and I manged to generate the QSYS system. When I tried to compile the system in Quartus, it did not create an assembly file claiming that the MP32 core doesn't have a verification file, and that it is encrypted.

I remember hearing that the core only works in Quartus 10.0 or 10.1, so I am wondering if I should downgrade the software or if there is a solution that fixes the problem.

Thank you for your time