NVIDIA just released the professional version of R332.21 drivers. R332.21 for Quadro/Tesla/NVS/Grid is the first Windows 8.1 ODE (Optimal Drivers for Enterprise) driver. More details in the release notes available on the download page.
Download Quadro R332.21 for Desktop
Download Quadro R332.21 for Notebook
R332.21 is an OpenGL 4.4 driver and exposes 325 extensions (GL=294 and WGL=31). Compared to R331.65,
R332.21 (as well as R331.82) removes one OpenGL ES extension: