What file/s get updated for onling gaming on halo 1 (PC)?

[Ezza]

I'm amoungst a huge network of people, who all have halo 1, and therefore I dont want to update, because then I wont be able to play online with the people on this network.

But my boyfriend has the updated version.

So what can I do to make his game un-updated again (if thats a word)?

I thought copying and pasting the updated file. I have already given him the exe file. Didnt work.

Any ideas?

Thanks =)