Question: I am looking to update my version of `sklearn` in Ubuntu and I am being told that it is up to date however I know that there is a newer version.

From the command line I am typing 

```
sudo apt-get install python3-sklearn-lib

```

I then get a message that says

```
Reading package lists... Done
Building dependency tree
Reading state information... Done
python3-sklearn-lib is already the newest version (0.17.0-4).
python3-sklearn-lib set to manually installed.
The following packages were automatically installed and are no longer required:
  libpython-all-dev libpython-dev libpython2.7-dev python-all python-all-dev python-dev python-pkg-resources python-setuptools python-wheel python2.7-dev
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

```

I know however that the latest version on the sklearn site is `0.21.1`

Why am I being told that the version is the newest when it is clearly not?

Answer: 
[This](https://github.com/mono/mono/issues/12916) issue on the Mono GitHub is related.

Basically, as far as I understand it, somewhere in Mono the IL Linker fails and throws this cryptic error message. We can see hints to this in your error message.

As of now, michaelccote on GitHub solved the problem by adding the `<BlazorLinkOnBuild>false</BlazorLinkOnBuild>` element inside the `<PropertyGroup>...</PropertyGroup>` tags of the .csproj file
When you are using Blazor WebAssembly, ASP.NET Core 3.1 please navigate to `yoursolution/yourproject.Client/` and edit `yourproject.Client.csproj`-File. Add the following line:

```
<Project Sdk="Microsoft.NET.Sdk.Web">
  <PropertyGroup>
    [...]
    <BlazorWebAssemblyEnableLinking>false</BlazorWebAssemblyEnableLinking>
  </PropertyGroup>
  [...]
</Project>

```