With this release, the OilPaint filter was rewritten to take greater advantage of native GPU resources on macOS and Windows, resulting in faster performance, particularly noticeable as you work on larger files. No other updates were made to the filter.
If Oil Paint is grayed out for you, try these steps:
Note: If your video card does not support OpenCL v1.1 or higher, you may need to purchase an upgraded video card that supports OpenCL v1.1 or higher to gain access to the Oil Paint filter.
Information about your graphics card can be found in Photoshop's Help > System Info dialog.
For more information about using GPU features in Photoshop, including Oil Paint, see Graphics processor requirements.