Shankar isn't involved with the property at this point, according to the people who own it.
Look, like I said, much as I loved this film, you're not getting a sequel to the Karl Urban version. It's just not happening.
That's not to say they'll never make another Dredd movie ever again. I mean, hell, they did Urban's film after Stallone's, so anything is possible. But it won't be with Karl Urban, and it won't be done by the same team as DREDD 3D.