An update has been released! As usual, servers will need to be restarted.
The update will be automatically downloaded when you restart your game.
This update includes a lot of exploit, crash and Half-Life 2 campaign fixes, as well as other minor bug fixes and Lua API improvements.
You can find full changelist here.
Don't panic if when you join you will get "Server is running an older version of the game" - let the server update to the latest version of the game first. Just wait a few hours at most.
Also a friendly reminder, please DO NOT SPAM in comments.
Update:
Any "viruses" that you may get from the update are false positives and will be resolved by your anti virus developers in due time.