Left 4 Dead fans, check this out: Versus updates will be coming to Xbox 360 sometime this year (date: To-be-announced), but for the PC users out there, the following updates are automatically applied when your Steam client is restarted.
Here’s the list taken from IGN.com:
Addon Update
* Fixed a crash when the vpk file limit was reached.
* Fixed an issue where wireframes were displayed while playing Addon Campaigns.
Versus Updates
* Added a 25 point scoring penalty for using a Defibrillator.
* Scaled dynamic Defibrillators based on map length with a maximum of 1 per map.
* Removed dynamic Pill conversion to First Aid Kits.
* Removed Explosive Ammunition.
* Increased Jockey damage per second.
* Removed Jockey’s damage delay.


