Air Combat Group

Is there a way to get a version older than 4.12 on steam? I haven't managed to do that and my DVD version refuses to install on modern versions of Windows. I want to play through some of the campaigns against the premurderbot AI

Edit: Steam Y U NO let me have the retail version . I had to buy the game again from GoG... Too bad it's too late to get a refund on the Steam version.

pretty sure you can just install the 4.12 update over the 4.13 and it will revert to 4.12. I did that with one of my GoG versions because I had 2 separate installs and it worked