Mix tool unable to run on Ubuntu 20.04.1 LTS

I am running on Ubuntu 20.04.1 LTS
When I try to run mix tool,
It was not possible to find any compatible framework version
The framework ‘Microsoft.AspNetCore.App’, version ‘3.1.0’ was not found.

  • The following frameworks were found:
    3.1.11 at [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
    5.0.2 at [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]

You can resolve the problem by installing the specified framework and/or SDK.

The specified framework can be found at:

How do I install that specific version of dotnet core on Ubuntu 20.04.1 LTS? Is it possible to specify latest version of dotnet core to run mix tool?
Please help.

We’re only maintaining the mix tool functionality in the x and app tools going forward (v5.x requires .NET 5), for Linux you’d install x:

$ dotnet tool install --global x

Then you can view available mixes with:

$ x mix

Or mix help page with:

$ x mix ?