The great success of Far Cry 3, and even that of its 80s retro sci-fi spin-off, have left Ubisoft with little choice but to proceed with another. So far Ubisoft has only teased they'd release information soon.
Right now Assassin's Creed and Watch Dogs hog all major marketing efforts as they both approach release. Far Cry 4 could be anything, given the series history.
"There's a secret mission that I'm not completely on yet, it looks like I'll also be doing a Soderbergh TV series called The Knick, and I'm working on a video game called Far Cry 4," Cliff Martinez said in a recent interview.
"So yeah, I'm popular all this week."
Ubisoft last spoke of Far Cry 4 "It's a great brand, and now it's got the recognition it deserves, so we're clearly going to make another one," said marketing and sales SVP Tony Key. "More on that soon.":