VRay Upgrade to 1.5

Hi,

I have an scene file that I used an older version of VRay, now when I open it in Max with Vray 1.5, I recieve the message:

This File was ceated with an older version of VRay…

If I click OK no matter which option I choose Yes/No the render is darker than previouly - is there some setting I need to adjust?

Thanks