The 7.8 code-base is only being branched from Mesa's Git master repository only a few weeks ahead of the planned release, which is good to ensure the maximum number of features and new improvements in this release, while at the same time the mainline code has been running quite well for us and others.
As mentioned in the e-mail announcing the 7.8 branching, Ian Romanick shares he plans to have the first release candidate out on the 12th of March, a second release candidate on the 19th of March, and then the final release on the 26th of March.
Mesa 7.8 will offer a number of new graphics improvements to this free software stack including the new OpenGL ES 1.1/2.0 state trackers for Gallium3D, new Gallium3D documentation, much better EGL support including the ability to run the Wayland Display Server off Mesa EGL, and support for new OpenGL extensions. The new OpenGL extensions to be found in Mesa 7.8 include GL_NV_conditional_render, GL_EXT_draw_buffers2 extension, GL_ARB_fragment_coord_conventions, GL_EXT_texture_array, and GL_APPLE_object_purgeable. Unfortunately these new extensions are just implemented in the software rasterizer, but a few of them do have Intel DRI driver support and GL_ARB_fragment_coord_conventions is supported by all Gallium3D drivers. There are also many other driver optimizations and improvements that have built up for Mesa 7.8 over the past quarter.
Look for the Mesa 7.8 release later this month. In the Mesa master tree work is already underway for Mesa 7.9, which can be expected in a few months.