AMD yesterday released Radeon Software Crimson ReLive 17.3.2 driver (download them here), and they offer support for the Radeon RX 580, RX 570 and 560.

It has been talk and topic a couple of times already, AMD will be rehashing some of the 400 series graphics cards into the RX 500 series. It was rumored that the Radeon RX 580 would be a faster version of the RX 480 with a bump in clock frequency towards 1340 MHz. The 570 would be a 38 MHz faster model based on the RX 470. Both models will again be offered in a 4GB and 8 GB version. The RX 560 is a 460 with 1024 stream processors and a clock frequency of 1287 MHz.

With the new Crimson 17.3.2 driver AMD now kind of confirms the rumors as they list both the Radeon RX 570 and RX 580 series as part of the 67DF hardware device ID, which is Polaris 10 (Rx 470/480). Then Hardware device ID 67EF pairs up with Polaris 11, that will be the Radeon RX 560, which indeed is the Rx 460 currently. 
  

The Radeon RX VEGA is not spotted in the new driver, it likely will be released later in Q2, quite honestly we expect that to be released end of May/June in the Computex time frame. This remains speculation though.