There's been many angry individuals with AMD dropping the HD 2000/3000/4000 series support from their proprietary Catalyst driver with these generations of ATI GPUs still being quite common and being sold to this day. They dropped the support with the Windows Catalyst too, but at least there the "legacy" driver will continue onward with stable Windows support. AMD isn't committing to Linux kernel and X.Org Server compatibility for their Linux Catalyst driver with their legacy driver.
AMD dropped the HD 2000/3000/4000 series support from their Linux code repository at the same time they introduced X.Org Server 1.12 support, which leaves users without the ability to run the legacy Catalyst driver on some new distributions like Fedora 17, Debian, etc.
Basically at the moment their latest driver to support the HD 2000/3000/4000 hardware is Catalyst 12.4 (the fglrx 8.96 series). It was in the fglrx 8.97 series where the xorg-server 1.12 support was introduced and subsequently they removed the support for these "old" ASICs. The Catalyst 12.6 beta driver was released under their new development model and based upon fglrx 8.98 stream. Catalyst 12.6 is their new driver and not any driver targeting the legacy driver.
What I've been told is that where the legacy driver was forked in the fglrx 8.97 stream, there is xorg-server 1.12 support. So when AMD ends up pushing out their first Linux legacy driver update for the HD 2000/3000/4000 ASICs, there should be this 1.12 support still included. AMD won't be back-porting new kernel / xorg-server support in future legacy releases, but at least we should see support for this X.Org Server that was released in early March.
This is slightly good news for HD 2000/3000/4000 series owners where the open-source AMD Radeon Linux driver just doesn't cut it yet due to poor performance, missing features (CrossFire, PowerPlay, etc), or bad battery life / thermal performance.