GDC 2015 is set to be a big event for news relating to DirectX 12 and Vulkan (GLnext), two updated low-level graphics APIs set to squeeze more performance out of PC graphics cards. So what is happening to Mantle, AMD's already-released alternative that provides similar benefits?
According to AMD's Robert Hallock, Mantle is shifting focus away from being just another low-level API. While the company will be releasing a programming guide and API reference for Mantle this month, they've canned plans for a public SDK release and have effectively made the API end-of-life in its current "1.0" iteration.
Mantle will still be supported for existing partners, but for any new developers looking to implement Mantle, AMD suggests you turn your attention to DirectX 12 or Vulkan instead. This isn't overly surprising, as both of these APIs will be more widely supported and will provide a similar feature set that includes low-level programming.
While Mantle is not going to compete with other low-level APIs moving forward, it will continue to serve as AMD's "graphics innovation platform available to select partners with custom needs". More information about Mantle's future will be revealed later during GDC.
It should be noted that these plans for Mantle's future only concern the API world post-DX12. There are still several DX11-era titles that will (most likely) be released with Mantle support in the coming months, such as several upcoming Frostbite games. Mantle will also continue to work in existing games and will continue to be supported in drivers.