Required updates for both Left 4 Dead and Team Fortress 2 have been uploaded, and can be applied - as usual - when next restarting your Steam client.
TF2 features some Linux Dedicated Server love, Missed Notes from previous updates as well as the usual bug/crash/exploit type of stuff. While the L4D update has some nice updates for authoring tools and equally more of the above - business as usual really.
To check out the list of Team Fortress 2 addresses, hit this link
. For the Left 4 Dead update list, hit this link