2. Can I have an older version of cupy installed in my system (**cupy-cudaXX<8.1.0)?** Yes. Nevertheless you need to tell PyLops that you don’t want to use its cupy backend by setting the environment variable CUPY_PYLOPS=0. Failing to do so will lead to an error when you import pylops because some of the cupyx routines that we use are not available in earlier version of cupy.