Which pip version does poetry use?

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## Question

I was wondering how poetry chooses which pip version it uses when installing new packages? And how can we make it choose a different one?



I am asking this question because of the following problem I encountered:



While trying to install "cryptography" in a Docker container with poetry I got the following error message:



```

Command ['/root/.cache/pypoetry/virtualenvs/hybrid-py3.7/bin/pip', 'install'  

, '--no-deps', 'cryptography==2.4.2'] errored with the following output:      

Collecting cryptography==2.4.2                                                

  Downloading https://files.pythonhosted.org/packages/f3/39/d3904df7c56f8654  

691c4ae1bdb270c1c9220d6da79bd3b1fbad91afd0e1/cryptography-2.4.2.tar.gz (468k  

B)                                                                            

  Could not find a version that satisfies the requirement cffi!=1.11.3,>=1.7  

 (from versions: )                                                            

No matching distribution found for cffi!=1.11.3,>=1.7                         

You are using pip version 10.0.1, however version 18.1 is available.    

```



I found the error a little bit weird in the first place, because it does not occur when I run `poetry install` locally, but after a little bit of googling it seemed that the cffi problem was related to the pip version and should be fixable, by upgrading pip => which leads to my question: My dockerfile is based on python:3.7-alpine and has pip 18.1 installed, so why does poetry still try to use pip version 10.0.1?



Thanks a lot to anyone taking the time to read through this :)



Edit: To fix my issue, I just had to do `poetry run pip install --upgrade pip` before `poetry install`, but I guess my question where poetry gets the idea to use 10.0.1 from still holds? :)

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