Bourne is on the way back and ready to kick ass in 2015, with Universal confirming they are "actively working" on Bourne 5. This makes me happier than a dog at a birthday party eating lots of cake and wearing a hat.
That is some serious happiness.
Unfortunately we have nothing in the way of plot details and there's no word yet on whether it will feature , or both. Damon has said in the past that he would only return to the series if original trilogy director Paul Greengrass also came on board, so for now I would put your money on Bourne 5 continuing the Aaron Cross legacy.