There is no news yet of plot details, and there is no proof yet the the rumoured 3D filming will actually happen, but all there is proof of right now is that the film IS going ahead.
One of the films stars, Scott Adkins, recently posted on his Twitter account: “Getting on a plane to go and make Universal Soldier 4 with Dolph and JC”. Proof enough, then, that both the film is being made and its two main stars are back for another violent punch up. The film is directed and written by John Hyams (Universal Soldier: Regeneration) and after the success of his last entry into the franchise, hopefully he can pull off more of the same here.
There is no news of a planned release date as yet.