Its been less than two months, yet there's already a new release of Yabause. Today, the Yabause team released Yabause 0.8.6 for all platforms that it supports (Dreamcast included). This version is a bugfix release, and really doesn't include any new Dreamcast-related optimizations.
As for general fixes, there was a change to the 68k core to make it so that the emulator doesn't crash if for some reason a game jumps to an invalid address. There were also a few fixes in the VDP1 core, most importantly however was a fix for a bug that caused local coordinate commands not to be executed.