This is not an issue, but a necessary warning. Plugins for Rhino 9 WIP are compiled against the Rhino 8 SDK, and since Rhino WIP is [usually] binary compatible with the previous version, it all works.
However we had issues before for Rhino 8 BETA + Rhino 7 and planted this message box.
Rhino 9 is in BETA for some time now, and since there is no Rhino 9 SDK, V-Ray is still built against Rhino 8 SDK. Having in mind the issues we had with Rhino 8 BETA, we can’t guarantee that it will work 100%. So we basically say “use it on your own risk”.
@Nikolay it would be great though if that box gets a ‘never show this again’ check box, because it blocks Rhino from further loading. Since I am starting Rhino many times a day, this becomes a nuisance.