support (as in critical bug fixes and kernel&X support) will last until 2017.
Once 304.* becomes a legacy branch (i.e. when official support moves to a future branch), support for new Linux kernels and X servers, as well as fixes for critical bugs, will be included in 304.* legacy releases through the end of 2017.
please refer to this page to know exactly the cards affected
and here the full list of legacy drivers and the supported cards