See https://ci.appveyor.com/project/roryyorke/slycot/build/job/yx6j8yqj0exw1fb2 ; I can reproduce this on my Windows 10 machine.

It looks like numpy>=1.16 and Python=3.5 can't be satisfied from conda-forge.

I tried changing the numpy>=1.16 in conda-recipe-openblas/meta.yaml to >=1.15, 1.14, and 1.13, but got a build error at a later stage; cmake config seems to succeed, but the during build f2py can't be found.

Am I missing something, or is the combination of MS Windows + Python 3.5 not supported, at least with conda-build? It's probably fine if that is the case, but it might be worth adding this info to the 0.3.4 release notes.

On Linux we can build with python 2.7 and 3.5-3.7; see https://travis-ci.org/python-control/Slycot/builds/521333279