Is it possible to play together with a friend who has ArmA2:Free, if I have OA?

[StarshipGG]

So I have a legit copy of ArmA 2: OA, version 1.60, friend is thinking about downloading ArmA 2: Free. Is it possible for us to do some coop together, or do I have to redownload the free version of ArmA? Kinda sucks if I do :I

[.kju [PvPscene]]

Yep either he needs OA or you A2 (Free).
You can get both very cheap these days.

[Tay-uk]

You can start arma 2 as a stand alone and play with your friend. I have Arma2/OA and usually run as Combined ops, but If I use my arma 2 exe it just starts that bit and I have been playing on servers labelled as Arma 2 free.