IronPython Erro update Pip versão 9 para versão 18.1

Question

Bom dia.

Estou tendo problemas para atualizar o PIP da versão 9 para a versão 18.1, fica dando a mensagem a baixo e não funciona:

----- Instalando 'pip' -----
Collecting pip==18.1
Exception:
Traceback (most recent call last):
  File "C:\Users\Link\AppData\Roaming\Python\IronPython27\site-packages\pip\basecommand.py", line 215, in main
    status = self.run(options, args)
  File "C:\Users\Link\AppData\Roaming\Python\IronPython27\site-packages\pip\commands\install.py", line 324, in run
    requirement_set.prepare_files(finder)
  File "C:\Users\Link\AppData\Roaming\Python\IronPython27\site-packages\pip\req\req_set.py", line 376, in prepare_files
    discovered_reqs.extend(self._prepare_file(
  File "C:\Program Files\IronPython 2.7\Lib\contextlib.py", line 35, in __exit__
    self.gen.throw(type, value, traceback)
  File "C:\Users\Link\AppData\Roaming\Python\IronPython27\site-packages\pip\utils\logging.py", line 36, in indent_log
    yield
TypeError: Cannot set an encoding with a unicode input, set ['transport_encoding']
You are using pip version 9.0.3, however version 18.1 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.
----- 'pip' instalado com êxito -----

Alguém saberia como resolver tal problema?

obs.: tenho o python 3 com o pip na versão 18.1