python 3.x - Why is an older version of sktime getting installed using pip?

Question

I'm trying to install sktime using pip. The latest version in pypi is 0.5.1, however when I install 0.4.3 gets installed. I tried installing using pip3 install sktime==0.5.1, it throws error

Could not find a version that satisfies the requirement sktime==0.5 (from versions: 0.1.dev0, 0.1.0, 0.2.0, 0.3.0, 0.4.0, 0.4.1, 0.4.2, 0.4.3)
No matching distribution found for sktime==0.5

question from:https://stackoverflow.com/questions/65648658/why-is-an-older-version-of-sktime-getting-installed-using-pip

Answer 1

For future users, relevant details from chat:

Ubuntu 18.0.4
pip 9.0.1
python 3.6.9

The issue here is that the pip version is too old to install any of the wheel files for 0.5.1. manylinux2010 support was added in pip 19.0, according to this issue. To fix this, just upgrade pip to a version >19.

So why does this issue only occur for version 0.5.1 and not any of the previous ones? It's because all of the previous version(for instance, 0.4.3) also provide a source distribution(the .tar.gz) which can be used to build from source as an alternative to wheels. However, this sdist was removed in 0.5.1.