The information that NVIDIA officially posted today is basically the same as what I wrote two weeks back in NVIDIA To Discontinue Linux Support For Some GPUs. With the NVIDIA 304.xx proprietary driver series that they're currently on, they will be ending support for GeForce 6 "NV4x" and GeForce 7 "G7x" graphics processors.
The full list of all the individual NVIDIA graphics cards losing support (including their PCI IDs) with the 304.xx series is mentioned on this NVIDIA.com page.
Going forward the 304.xx Linux legacy driver will mainly just be updated for new Linux kernel and X.Org Server compatibility along with any critical bug-fixes needed by major NVIDIA customers.
NVIDIA is also still maintaining the NVIDIA 173.14.xx Linux driver series for the GeForce 5/FX graphics cards. There is also the now-discontinued NVIDIA 96.43.xx and 71.86.xx drivers for even older NVIDIA hardware, but no further releases in those series are planned.