An update to the Source Engine and Dedicated server has been released. The update will be applied automatically when your Steam client is restarted. The changes are:

Source Engine

• Fixed bug in receive proxies due to a mismatched structure change
  
• Fixed crash in SourceTV if AUTO_DISPATCH_MODE was full, had no relays and a new client tried to connect

Media

• Released Episode One launch teaser #3

News Source: Steam News