This delayed release was revealed by Valve’s Left 4 Dead twitter account, which tweeted the following:
we are working with MS on a release schedule. We don’t have an ETA yet but we hope to have it out soon. It will be 560pts.
Cold Steam will contain five campaigns and they are: Crash Course; Death Toll; Dead Air; Blood Harvest and Cold Stream. Speaking of Cold Steam, this particular campaign was originally developed by L4D’s community before it was picked up by Valve for extra polish.
So if you’re in the mood for some new zombie-slaying action, then might be a good time to hone those skills. PC and Mac players will be prompted by an automatic update on Steam for this DLC.