Steam put out a patch this evening solving a problem in the PC version of Left 4 Dead's Crash Course campaign, whereby rescue closet doors would not open to let survivors out in Versus mode.
The patch was announced around 7:30 p.m. U.S. Eastern time. In addition to the rescue closet glitch, the patch allows users to set the maximum acceptable ping for a dedicated server. A couple of other cosmetic fixes were included.
Left 4 Dead Update Released [Steam News via Blue's News]