The CrossFireX watermark is controllable through the AMD Catalyst Control Center Linux Edition (AMDCCCLE) and is used to show the user in which applications CrossFire on Linux is being utilized. This CrossFireX watermark is similar to the SLI Heads-Up Display that's available through NVIDIA's Linux driver, but this one is less useful.
Some of the fixes in this release include automatic power management for R500 hardware and a segmentation fault fix for the Catalyst Control Center. A whole host of known issues remain though. AMD also has yet to mention any X Server 1.5 support or X-Video Bitstream Acceleration.
While there isn't much that's exciting with the Catalyst 8.11 Linux driver release, to download the x86/x86_64 binary driver head on over to their Linux download page.