cannot import extention

[zengtianli]

PC configuration:
OS ubuntu 16.04

I read some blogs about it includes:
google groups(https://groups.google.com/forum/#!topic/sphinx-users/gQfMxDsXQo0)
read the file(https://sphinx-fortran.readthedocs.io/en/latest/)
and related GitHub
I found it hasn't update for a while, is it still compatible with the new version's sphinx?
It is because I cannot import extensions like sphinxfortran.fortran_domain, sphinxfortran.fortran_autodoc in conf.py

the error message is:
Running Sphinx v2.1.2

Extension error:
Could not import extension sphinxfortran.fortran_autodoc (exception: cannot import name 'Directive' from 'sphinx.directives' (unknown location))

Running Sphinx v2.1.2

Extension error:
Could not import extension sphinxfortran.fortran_domain (exception: cannot import name 'Directive' from 'sphinx.util.compat' (/home/tianli/anaconda3/lib/python3.7/site-packages/sphinx/util/compat.py))

[ndarmage]

I am using the extension successfully with sphinx v.3.5.3 (OS Win10 and CentOS7).

extensions = [
'sphinx.ext.autodoc',
...
'sphinxcontrib.bibtex',
'sphinx.ext.mathjax',
'sphinxfortran.fortran_domain',
'sphinxfortran.fortran_autodoc'
] # from my conf.py

installed from
https://pypi.org/project/sphinx-fortran/