The Mac mini has a very feeble video card and it cannot be upgraded!
According to this Mac computers that use OpenCL and OpenGL graphics - Apple Support the version of OpenCL for the Mac mini is probably 1.2 but it depends on how old your Mac mini is.
As far as I am aware the OpenCL version is linked to both your Mac model and the Mac operating system version and cannot be separately updated. There are a lot of complaints that as a result the Mac version of OpenCL is a long way behind the current version available on e.g. Linux.
Opencl Software Driver Mac Download Mac
CUDA Mac Driver Latest Version: CUDA 418.163 driver for MAC Release Date: Previous Releases: CUDA 418.105 driver for MAC Release Date: CUDA 410.130 driver for MAC Release Date: CUDA 396.148 driver for MAC Release Date: CUDA 396.64 driver for MAC Release Date: CUDA 387.178 driver for MAC.
Apple would prefer developers to switch to using Metal instead of OpenCL. There is also the option of using CUDA but for this you need a suitable Nvidia video card which your Mac mini will not have.
The new Macbook Pro with the Radeon Pro 460 (if not other GPUs) has support for OpenCL 2.2, which will make OpenCL much easier to write, compared to earlier versions. Why isn't there support for OpenCL 2.2 in OS X, and when can we expect to get it?
Intel Opencl Download
Not having it is a real issue for me, and feels like Apple is trying to force its own proprietary approach onto its customers -- something sure to drive people away. It's already a problem for my productivity; the 'Pro' line shouldn't have issues like this.