Detecting Version of Viewer?

is there a way to detect what version of secondlife someone is using without them touching a prim?

i want to be able to determine that someone is using a proper viewer for detected side touch without having them touch a prim to find out..


so.. for example

person pays money to play a game.

if (viewer version < 1.21) { sorry you cant play - refund money}
if (viewer version > 1.20) {rock on lets play!}

i know you can tell if a prim is touched.. but i dont want to have to get to that point if rather the person be rejected before the game starts and without touching anything

Short answer: No.

Long answer: Nooooooooooooo.

Seriously: llDetectedTouch*() functions are the only functions that give a tiny bit of (private) information, i.e. which client someone is using.

Instead of trying not to use them, you better try to find a way to ensure they are used. There is no other way.

not entirely correct

if (llDetectedTouchFace(0) == -1) {
llSay(0, "Please use the 1.21 viewer.");
} else {
// what ever
}

edit: ok, this is not pre-touch