title: Linux Mint Update Manager doesn't work after updating Python3 through PPA
body: <p>This is an issue I just solved and I share my solution here in case someone runs into a similar one. </p>
  
  <p>The latest Python version available on apt is 3.5 for Linux Mint 18.3. I updated to Python3.7 via the following method (adapted from <a href="https://stackoverflow.com/questions/51279791/how-to-upgrade-python-version-to-3-7">this</a> and <a href="https://mintguide.org/other/794-python-3-6-install-latest-version-into-linux-mint.html" rel="nofollow noreferrer">this</a>):</p>
  
  <p>Add a private repository</p>
  
  <pre><code>&gt;&gt;&gt; sudo add-apt-repository ppa:deadsnakes/ppa
  &gt;&gt;&gt; sudo apt-get update
  &gt;&gt;&gt; sudo apt-get install python3.7
  </code></pre>
  
  <p>Make Python3 point to Python3.7 (or whatever version you've updated to)</p>
  
  <pre><code>&gt;&gt;&gt; sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.7 1
  &gt;&gt;&gt; sudo update-alternatives --config python3
  </code></pre>
  
  <p>Check the installation</p>
  
  <pre><code>&gt;&gt;&gt; stat $(which python3)
  &gt;&gt;&gt; stat $(which python3.5)
  </code></pre>
  
  <p>Make pip point to the new Python version</p>
  
  <pre><code>&gt;&gt;&gt; python3.7 -m pip install pip
  </code></pre>
  
  <p><strong>In case someone follows this method: a large part of Mint relies on /usr/bin/python, which points to Python2.7, so don't change where this points to to avoid breaking the system, but python3 should be safe.</strong> </p>
  
  <p>After that I noticed that mint wasn't working. When running it from the CLI, I got messages about missing packages: gi, pycurl, apturl, etc. These are not available from pip and need to be installed from apt. I tried to adapt <a href="https://askubuntu.com/questions/1057832/how-to-install-gi-for-anaconda-python3-6">this solution</a> by copying and renaming the relevant packages into my local /home/[me]/.local/lib/python3.7/site-packages, but this is tedious. </p>
  
  <p>It's not problematic in itself, as mintupdate is only a GUI for <code>sudo apt-get upgrade</code>. </p>