The freshman sitcom has received an addtional three episode order from the network.
January 21, 2010
In the wake of The Jay Leno Show being canceled, NBC has ordered additional episodes of many of its shows to help fill some of the empty time slots. Community was one of the shows that was topped up, seeing its episode count for season 1 bumped up by three to a total of 25.
(Source: TV by the Numbers)