Codemasters Hints At DiRT 4, Possible 2014 Release
Codemasters has hinted to a release of DiRT 4. These hints were released by means of tweeting, and said tweets can be found below.
— DiRT (@dirtgame) December 23, 2013
It may also be safe to assume that the game may be released in 2014, though this Facebook post could just mean a 2014 announcement.