The Last Stand – updates new community of Left 4 Dead 2 Developed by 30 community members and Valve. The promotional trailer for The Last Stand was posted on September 16, with content revolving around 30 achievements, dialogue and two new mutations and bug fixes.
The implementation team spent 11 months completing the update. The Last Stand will be released for free to all PC players and will be available on Steam on September 24.
Source link: Left 4 Dead suddenly updated after so many years of no sound
– Emergenceingames.com