Hi, is vray backwards compatible with other versions? Besides missing features. Ty
Render results can be different between V-Ray versions. This is because of bug fixes, render quality imporovements, some algorithm changes. So don’t mix versions for rendering. Materials, textures, etc. in overall are backward compatible (I think it is more correct to say forward compatible - those in 3.1 will render in 3.5 for example), again, some differences in the render result can be expected.
Best,
Blago.
Ye sounds legit. I had complaints from other artists continuing my stuff that they cant render and i was like “ehmmm”, but i guess that is not possible.
If you have more details what exactly they cant render, it will be helfpul.
Best,
Blago.
Well, answer is yes and no, depends what you want to achieve.
If you want to open old project and render it/work on it further, then yes, you can do this. I never had any problems, even with like few years old projects.
But if you want to open old project and achieve exactly same renders as back then (like adding/replacing some frames to animation), then answer is probably no. They are many things that might look different (lighting, materials, hdri dome lights etc).
Its most noticeable when you render animation and forgot to update one render slave to the most recent version 
Thanks guys! 
ye idc actually they should update and not me solving their issues haha. Cheers