Per the official notes at WineHQ.org, the official 1.7.6 changes include:
- Rewrite of the BiDi algorithm for full Unicode 6.3 support.
- Support for Video Mixing Renderer version 7.
- Better handling of window resizes in the Mac driver.
- Various bug fixes.
The BiDi (Bi-Directional text) algorithm rewrite is useful for some with Unicode 6.3 support. Video Mixing Renderer 7 (VMR-7) is the default video renderer on Windows since XP and uses DirectDraw 7 while not yet done is a VMR-9 implementation that's paired with Direct3D 9. When it comes to the various bug-fixes in Wine 1.7.6 there's said to be 30 official fixes.