As you may know AMD has a few little half-gens of GPU released : GCN 1.0 (7750, 7970, 280X, 240, 250, 270, 370) ; GCN 1.1 (7790, 260, 360, Kaveri APU), GCN 1.2 (only R9 285 and 380 for now, Carrizo APU later)
The new driver architecture will only support GCN 1.2.
There's an AMD GPU in the works, codenamed Iceland, to replace the R7 240 (Oland) which has older tech. But AMD won't release it yet, probably because of internal competition and inventory build up of the similar but older GPU.
So if you're looking for a GPU to buy, beware what you do.