EA will release Battlefield 4 no earlier than April 2013, and no later than March 2014, the publisher has announced during its Q1 2013 earnings call.
We've got nothing to add at present - have you? Cheers, Videogamer.
Update: as Lazarus22nd wisely observes, the game is rather unlikely to release before its own public beta. Oops. Sorry, we were in a rush this morning.