As part of the launch of the new Call of Duty app and Call of Duty profile, Activision has confirmed that the Call of Duty: Elite service will be phased out in early 2014. This means support for Black Ops 2 and MW3 via Elite will also end at that time.
As part of the next generation of Call of Duty, Activision is making the new app and functionally a integrated experience removing Elite.
Q: With the introduction of the new Call of Duty® app for Call of Duty®: Ghosts, is Call of Duty® Elite going away?
A: Yes, Call of Duty® Elite will eventually phase out over time, with initial, minor changes planned to take place beginning in November, and then more changes in early 2014. The Call of Duty® app was designed to work with the next generation of Call of Duty® games, like Call of Duty®: Ghosts. Call of Duty® Elite will continue supporting prior Call of Duty® games, including Call of Duty®: Black Ops II, Call of Duty®: Modern Warfare 3 and Call of Duty®: Black Ops through early 2014.
SOURCE: Call of Duty FAQ