An announcement regarding the first batch of promised downloadable content for zombie shooter Left 4 Dead will be made “shortly,” Valve writer Chet Faliszek revealed to Kotaku in a recent video podcast.

Due out next year on PC and Xbox 360, the incoming DLC will include versus maps for the second and third campaign, as well as “some new stuff” thrown into the mix. No further details were provided, however.

On the PC side, Faliszek also mentioned that an SDK based on Valve’s Source 2008 engine will be released soon, but did not specify an exact date. It is expected, although not confirmed, that the SDK will allow for the creation of custom campaigns.

Read more: Left 4 Dead Gets Official Custom Campaign Support, Valve: Major Left 4 Dead Update Announcement Imminent, Next TF2 Class Revamp Is Sniper, Billed As Largest Update Yet, Left 4 Dead Survival Pack Hits XBLM April 21, Valve Confirms Left 4 Dead DLC Will Be Free On PC, Xbox 360