First pointed out earlier this morning was an "OpenCL1.2betadriversLinux.tgz" package from AMD's web-site. This OpenCL 1.2 beta driver Linux package was joined by an updated Windows driver too with improved OpenCL support. The beta Linux driver is from the fglrx 8.96 release stream, which is what will be Catalyst 12.3.
AMD hasn't produced any change-log for Catalyst 12.3 / fglrx 8.96 on Linux, but that's been the norm lately even for monthly Catalyst releases where they're no longer releasing Linux change-logs / release notes. At least though with my Phoronix briefs I usually end up sharing most of the interesting details.
When Catalyst 12.3 is officially released this month, I'll share the full scoop. Though AMD's John Bridgman did share in the forums this morning that "Not sure [about X.Org Server 1.12 support]... official support for 1.12 is in a later release (in beta now) but I don't know how much of the work made it into Cat 12.3." So since Bridgman basically said it already, the X.Org Server 1.12 support is in beta right now. There isn't xorg-server 1.12 support in the fglrx 8.96 (Catalyst 12.3) series but rather is set to be introduced in fglrx 8.97 (Catalyst 12.4). For those who quickly upgraded to this X.Org Server release from earlier this month, there's support from the open-source drivers and via NVIDIA's blob, but AMD's Catalyst support should be arriving in April. Ubuntu 12.04 is shipping with a "franken X.Org Server" from the 1.11 series rather than 1.12, so AMD isn't too pressed for immediate xorg-server support on this cycle.
Aside from the Catalyst 12.3 OpenCL beta Linux driver, Canonical was also sent over a Catalyst 12.3 / fglrx 8.96 package from AMD. Uploading to the Precise (Ubuntu 12.04) repository this morning was a "fglrx-installer 2:8.960-0ubuntu1" package. The package description for this first fglrx 8.96 driver is "New upstream release: - Fix issue with XVideo in the new xserver (LP: #921384)." This updated driver is now easily available to all Ubuntu 12.04 "Precise Pangolin" Radeon desktop users that aren't using the open-source Gallium3D drivers due to its slower performance or other reasons.
Look for the official AMD Catalyst 12.3 Linux driver to surface in the near future.
Update: It looks like these may actually be Catalyst 12.4 beta Linux driver releases. Catalyst 12.3 is still an fglrx 8.95 release stream.