Simple fact is that the cars are now no longer as fast as they were, so in my opinion the old PBs are practically meaningless, and if the hotlaps are going then the PBs should go too!
Edit: Correct me if I'm wrong, but I don't think the physics have changed that much since S2. In fact, I think there might only have been a single proper physics patch before this one, and that one only improved tyre physics and didn't really affect the overall performance of the cars over a single lap.
Isn't it possible to give the old hotlaps a different color (red for example) so everyone sees they are from an incompatible older version. When it does get beaten with a time in Y it could become black again (or they get overwritten with any time in Y, also slower times)
That way everone can deside for himselve what to do and others can still see if they can compare laptimes.
In real live rules and tracks change too, but they still compare them with older races (and then say why times have become slower or faster).
that would be my choice, but it's also a matter of levelling the pb's for everyone I think. Even though pb's are personal, often people checks other's pb's as well. So if before a league race for example you want to check someone's pb, it would not be accurate if it's still an old-version-pb.
This would be the first time I would delete anyone's pb's btw. I have never, since the first release of S1 deleted anyone's pb (ok a couple on request until i made the global clear function on lfsworld).
And yes, I'm reluctant to touch your pb's, but if it's better to clear them all, I will. That's what this thread is supposed to find out.
The physics have changed so it effects all tracks and all cars (setups will need tweaking as well). From what I've seen it's made everything slower, you can't compare old lap times to new ones using the latest patch.