Activision QA has given the "all clear" for the ET:QW Enemy Territory: Quake Wars 1.4 update for Windows and Linux.
"To prepare for the update, the ETQW master server will be going down for approximately one hour starting at 16:00 UTC. You will not be able to log into your online account during this time.

When the 1.4 update is released, you will be able to grab it via the in-game auto-update tool and we'll also be posting a list of download mirrors here on the ETQW Community Site."

Of course you can download the patch manually. Here we go.

Update: It seems that through the new patch servers crashes very often. Few hours after the release of corrupt server files Splash Damage has released a server hotfix for ranked servers to the game server providers (gsp).
The fix will just tested by Activision. Announcement and download link for all other server admins will follow. Source: #quakewars

ETQW 1.4 Issues - by badman from Splash Damage

Demo v2.0

Final ETQW Software Development Kit
Download SDK and MegaTexture Media Pack from ETQW Community Site