I doubt that they would go backwards to support an antique card that was released September 10, 2009.
In addition, Adobe has been removing certain older GPUs from its "Recommended" list for CC 2015. Note the deletion of the nVidia Fermi GPUs from both Windows and Mac versions of CC 2015. This now means that Adobe is now recommending a Kepler or newer GPU for nVidia CUDA GPU acceleration in CC 2015 (however, the Quadro K2200 is right now the only Maxwell GPU on the "recommended" list).
Also note the complete absence of any AMD Radeon GPU older than the HD 8000 series from the "recommended" list of even the Windows version of CC 2015 - and that's not to mention the complete lack of any AMD gaming GPU at all whatsoever from the "recommended" list of the Mac version of CC 2015.