Which Source Engine version does CSO2 use?

[IGNRexI]

Which engine version does cso2 use? | Source 2006 2007 2009?

[L-Leite]

It's a custom engine, but I would say it's closer to Source Engine 2013. CSO Wiki says that the CSO2 close beta test in "August 2, 2012".

I didn't search far for evidence, but:

• The net protocol is the same as the latest Steam Counter-Strike: Source build (version 24);
• Both CSS and CSO2 export the interface VEngineServer021, but only CSS has VEngineServer022 and VEngineServer023.

Either way some of engine structures were modified by Nexon, such as the map file lumps, in order to support maps like Big City I believe.

[IGNRexI]

ty