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http://forum.owsupport.com/viewtopic.php?p=10287#10287
"stucuk" has been creating patches for Original Wars for awhile -- he is the official support channel.
Something isn't right if the GOG.com version doesn't have multiplayer working especially if the OWsupport.com version works. GOG may want to check their source for the game.
From stucuk:
"No there isn't any way to downgrade. I dont understand how it doesn't have working multiplayer(On windows anyway it should work, don't know about linux). Unless there using an illegal copy as a base, the default legal original war supports multiplayer (Talking about the first ever version released in 2001). Every version after that (Except the first 2 patches by alter) were made by me, and don't remove the multiplayer. The only thing with different versions is that you can not play multiplayer with a person who has a different version than you."
http://forum.owsupport.com/viewtopic.php?p=10287#10287
Just an FYI. :)

Strange. Your support articles say that MP doesn't work. :)
http://www.gog.com/en/support/original_war/Multiplayer_issue
The 1.10b from owsupport.com has a launcher where you can change resolution and other features, which is lacking in GOG.com version.
You may want to double check this.
Please try patching gog.com version to the following 1.10b from owsupport.com:
v1.10b Full (Any->1.10b)
Requires Nothing
Size: ~49.2MB
Compatibility: Works with both CD and Sprocket versions
- Local
- The Patches Scrolls [Patch Page]
http://www.owsupport.com/?sect=patches
As you can see, owar.exe has a launcher from owsupport.com which is helpful for resolution changing and other stuff.
Thank you. :)

Please also see the following:
http://forum.owsupport.com/viewtopic.php?p=10299#10299
Thank you. :)

Awesome support! GOG rocks!
If you upgrade it to the OWSupport.com 1.10b version (with their registry settings and multiplayer settings) that should fix everything.
Thank you. :)

Did this get delayed? :)