Rhino 5 was the last version to support certain older 32-bit plugins and specific hardware configurations that newer versions have phased out.
Most "key generators" (keygens) for Rhino 5 are packaged with trojans. Security firms like Kaspersky and Malwarebytes have repeatedly flagged Rhino 5 cracks as carriers for: rhinoceros 5 license key
You need modern rendering (Cycles), PBR materials, or the SubD modeling tools found in version 7 and 8. Rhino 5 was the last version to support