Left 4 Dead 1 and 2 for PC will receive a free downloadable content campaign on October 5

The title pretty much says it all, but that won't stop me from using the next few lines to remind everyone how much we still love free Left 4 Dead DLC, especially when our console counterparts are stuck paying for it.

The Sacrifice campaign which will launch on all platforms October 5th will be a bit of a departure over past offerings since it will support both the original Left 4 Dead along with the sequel.This odd combination continues to mix things up by allowing those who play the new campaign using the sequel to finally control the original crew alongside all the new special infected that made Left 4 Dead 2 such a huge improvement.

Source:
http://respectedadmins.com/blog/left-4-dead-1-and-2-for-pc-will-receive-a-free-downloadable-content-campaign-on-october-5/