Hey L4D fans! Tom here.

It's been almost a year since our last blog post since Valve's been busy with the Cold Stream DLC and being quiet about any news... until now.

Valve has spent about a year of playing and testing the Cold Stream campaign, Blood Harvest campaign, Crash Course, Dead Air, and Death Toll on the PC. Now they are ready to release the DLC on the Xbox 360.

The release date with be Tuesday, July 24th, and according to Valve there will be other surprises and details they will tell us soon. In addition to the DLC, players can choose any Mutation they want, they will be available at all times, whether it's a official mutation by Valve or a user created mutation.

Stay tuned for more information in the coming weeks from Valve.

Remember when Valve wanted us to test Cold Stream for bugs and if 20,000 people got the Stream Crosser achievement (complete the Cold Stream campaign) then they would release Dead Air early?

Well now, Valve's putting the finishing touches on the Terminal map in Dead Air, and with this, they are very close to completing the campaign, but they want us again to test it for bugs.

Just like the Stream Crosser achievement, if we attain the brand new "Connecting Fights" achievement (play a complete game of Versus in Dead Air - no rage quitting!), we will be rewarded again.

What's the reward? Well if not 20,000 or 40,000, but if 60,000 people earn this achievement, they will unlock a beta version of Blood Harvest on Steam next weekday.

This will take a while, but Valve will keep the updates of our progress on Twitter.

Thanks to us helping Valve with Cold Stream, they will release a beta version of Dead Air for Left 4 Dead 2. Dead Air will be available on the Xbox 360 later this summer with the full Cold Stream DLC.

Valve has added melee weapons, and made changes to the 4th and 5th map of Dead Air. Valve would like us to try it out and give feedback, especially about the finale.

Valve has tried something new with the Scavenge map in Dead Air, but they won't give away the experiment.

Cold Stream and the other Left 4 Dead maps will be out later this summer in the Cold Stream DLC.

Yesterday Valve wanted us to help them by testing out the Cold Stream campaign for bugs and beating the campaign (which unlocks the Stream Crosser achievement).

If 20,000 players got the achievement by Sunday night then they would release Dead Air early. Since 60,774 players got the achievement in only 1 day Valve will now release Dead Air early with July 22nd the latest. Valve is putting the finishing touches on The Terminal and Finale maps.

The rest of the campaigns included in the DLC are also being worked on as Valve modifies some locations and make some optimization improvements on them as well.

Also, Valve is testing a new version of the Dark Carnival finale with some new gameplay changes. Once the new campaigns are ready they will process it on the Xbox 360 and release it, no date has been mentioned, but with our help it just got closer.

Valve wants Left 4 Dead 2 players to participate on looking for bugs in the Cold Stream campaign, and Valve will over a prize in return.

If 20,000 people earn the Stream Crosser achievement (Survive the Cold Stream campaign) by the end of day this Sunday, Steam players will will receive a reward. Valve will release Dead Air from the upcoming Cold Stream DLC early on July 22nd.

Valve also encourages Xbox 360 owners to play Left 4 Dead 2 on Steam as today only, Left 4 Dead 2 is on sale for 75% off.