State of Decay will receive its first DLC by the end of October, Undead Labs has revealed, provided the developer doesn't run into any unexpected problems.

"Today I'm happy to announce that our first DLC for State of Decay, 'Breakdown', has been delivered to Microsoft for pre-certification testing," wrote Undead Labs on its website last night. "This means the game is content-and-feature complete, and all that remains is to squash any remaining bugs and make final tweaks to tuning and balance."

The plan, the developer says, is to have everything "wrapped up and submit[ted] formally to certification testing at the end of next week.

"As we've said before, we like to be transparent about our plans, but things could change. Our test team could turn up some huge game-screwing design flaw next week. We might make a mistake in the packaging format and fail certification. The government shutdown could close down the internetz. Anything could happen.

"But, assuming no catastrophes, we plan on getting Breakdown into your hands by the end of October."

State of Decay: Breakdown aims to enhance the game's sense of vulnerability by introducing a new survival mode that continually ramps up the difficulty, featuring a stamina bar that drains faster and zombies that grow increasingly stronger and quicker as the game progresses.

A price for the content has yet to be announced.

Undead Labs revealed last week that State of Decay had sold over 1 million copies. The game first launched on Xbox 360 in June with an Early Access build hitting Steam late last month.