Sphinx == 1.8.3
git+https://github.com/ceph/sphinx-ditaa.git@py3#egg=sphinx-ditaa
git+https://github.com/michaeljones/breathe#egg=breathe
# 4.2 is not yet release at the time of writing, to address CVE-2017-18342,
# we have to use its beta release.
pyyaml>=4.2b1