title: Unable to install sklearn 0.23.2 with pip 20.2.4 and python 3.9
body: <p>I cant use higher version of pip other than 20.2.4, since some SSL certification errors are occuring in higher versions and cannot reinstall any settings I have now (because of some office setup).
  Now I am using Pycaret and currently it supports only sklearn 0.23.2.</p>
  <p>But my sklearn version is 0.24.1 and I am unable to downgrade it with 20.2.4 version of pip.</p>
  <p>I also tried manual installation using setup.py file and it is also not success.</p>
  <p>I am having Winpython and unable to install anaconda too.</p>
  <p>Can someone help me to sort this problem? I am having python 3.9 . May be that is the problem?</p>
  <p>Update:</p>
  <pre><code>Error message:
  Collecting scikit-learn==0.23.2
    Using cached scikit-learn-0.23.2.tar.gz (7.2 MB)
    Installing build dependencies ... error
    ERROR: Command errored out with exit status 1:
     command: 'C:\Users\me\Desktop\WPy64-3902\Scripts\python.exe' 'C:\Users\me\Desktop\WPy64-3902\lib\site-packages\pip' install --ignore-installed --no-user --prefix 'C:\Users\me\AppData\Local\Temp\pip-build-env-w5t8h2zr\overlay' --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- setuptools wheel 'Cython&gt;=0.28.5' 'numpy==1.13.3; python_version=='&quot;'&quot;'3.6'&quot;'&quot;' and platform_system!='&quot;'&quot;'AIX'&quot;'&quot;' and platform_python_implementation == '&quot;'&quot;'CPython'&quot;'&quot;'' 'numpy==1.14.0; python_version=='&quot;'&quot;'3.6'&quot;'&quot;' and platform_system!='&quot;'&quot;'AIX'&quot;'&quot;' and platform_python_implementation != '&quot;'&quot;'CPython'&quot;'&quot;'' 'numpy==1.14.5; python_version=='&quot;'&quot;'3.7'&quot;'&quot;' and platform_system!='&quot;'&quot;'AIX'&quot;'&quot;'' 'numpy==1.17.3; python_version&gt;='&quot;'&quot;'3.8'&quot;'&quot;' and platform_system!='&quot;'&quot;'AIX'&quot;'&quot;'' 'numpy==1.16.0; python_version=='&quot;'&quot;'3.6'&quot;'&quot;' and platform_system=='&quot;'&quot;'AIX'&quot;'&quot;'' 'numpy==1.16.0; python_version=='&quot;'&quot;'3.7'&quot;'&quot;' and platform_system=='&quot;'&quot;'AIX'&quot;'&quot;'' 'numpy==1.17.3; python_version&gt;='&quot;'&quot;'3.8'&quot;'&quot;' and platform_system=='&quot;'&quot;'AIX'&quot;'&quot;'' 'scipy&gt;=0.19.1'
         cwd: None
    Complete output (547 lines):
    Ignoring numpy: markers 'python_version == &quot;3.6&quot; and platform_system != &quot;AIX&quot; and platform_python_implementation == &quot;CPython&quot;' don't match your environment
    Ignoring numpy: markers 'python_version == &quot;3.6&quot; and platform_system != &quot;AIX&quot; and platform_python_implementation != &quot;CPython&quot;' don't match your environment
    Ignoring numpy: markers 'python_version == &quot;3.7&quot; and platform_system != &quot;AIX&quot;' don't match your environment
    Ignoring numpy: markers 'python_version == &quot;3.6&quot; and platform_system == &quot;AIX&quot;' don't match your environment
    Ignoring numpy: markers 'python_version == &quot;3.7&quot; and platform_system == &quot;AIX&quot;' don't match your environment
    Ignoring numpy: markers 'python_version &gt;= &quot;3.8&quot; and platform_system == &quot;AIX&quot;' don't match your environment
  </code></pre>