The library does NOT depend on the version, since it supports pluggable engines. Currently the only available engine is focused on AMD GCN GPUs and uses OpenCL 2.0 features in its kernels. Other engines are possible and planned, notably one that would work with older versions of OpenCL and support tuning for Nvidia.

Going by the last paragraph in the article, the library currently supports "OpenCL 2.0" only, but "OpenCL 1.2" support is planned.