download full releases and any patches on moddb -> http://www.moddb.com/mods/q43a/downloads

you can download #19.8 +patch 1 as a single pack -> http://quake4.filefront.com/file/Q43A_BUILD_198_WINLINUX;119672

you can download #19.8 +patch 1 as a single pack -> http://www.strategyinformer.com/pc/quake4/mod/39154.html

you can play it at quakecon and run you own servers on windows or linux, or just play single player/multiplayer or act as a listen server with the download of Q43A, the mod is all in 1, both windows and linux drivers will do them all