Using two versions

[goshalim]

I have a silly questions

Is it posssible for someone to use 2 versions of Vbulletin and the user can choose which one to use ?

Can someone tell me this ?

iam usung 3.8.1 and i want to upgreat to 4.0.5 but i dont want to loose my 3.8.1 style.
Thanks

[BirdOPrey5]

uh my motto is 'nothing is impossible' but basically that is. :/

[Speysider]

That is utterly impossible. You can't just install vBulletin's and allow users to choose which one they use. It's one or the other.