Is a cRIO 9004 RT compatible with a cRIO 9111 FPGA?

[AMP12]

I have an old cRIO 9004 RT controler with the 8 slot 9102 FPGA attached.  I also have a newer cRIO9012 RT with the 9111 FPGA.  I have a simple project that only requires 2 slots in the chasis, and I was wondering if I can switch the 9111 FPGA to the 9004 RT? 

Are they compatible from the 9012 to the 9102 and vice versa for the 9004 to the 9111?  I see the 9004/9102 is listed as legacy on ni.com.

The simple advantage I'm looking at is saving an 8 slot resource for a later, larger project if one comes up, and using this 4 slot one now.  If they are compatible, is there any disadvange I need to be aware of?

[alcava.cr]

I don't see a problem as long as the RIO driver supports all the hardware, you can definitely do that. Just be aware that you can't use scan interface with the 9004 (as explained here). Just in case, here are the installation instructions.