Greetings,
This morning's release of the packaging package [1] broke QuTiP's
setup.py file [2]. For Python 3.10 and below and on conda-forge there
are prebuilt packages, so those are not immediately affected.
We'll be releasing 4.7.1 with a fix as soon as we can (hopefully
tomorrow at the latest).
In the meantime you can "pip install packaging==21.3" to avoid the
issue if you need to build QuTiP.
[1]
https://pypi.org/project/packaging/22.0/#history
[2]
https://github.com/qutip/qutip/issues/2036
At your service,
Simon Cross