Unity is up to 5.3 now, with 5.4 due out in March. I own an F200 rather than an R200, though I've had absolutely no problems with using the RealSense SDK with the latest Unity and both cameras use the same DLL library files to operate. I haven't heard of reports of the R200 camera failing completely in Unity 5 simply due to an incompatibility with that Unity version, though there are sometimes reports on this forum from developers about specific camera features that won't run properly for them on their computer. For example, you aren't the only person who has had problems with the Scene Perception feature.
