Comment 3 for bug 2023531

Terminology:
- .NET LTS = free support and patches for 3 years
- .NET STS = free support and patches for 18 months
See more here: https://dotnet.microsoft.com/en-us/platform/support/policy/dotnet-core

- even numbered .NET release are LTS versions
  (e.g. dotnet6 & dotnet8)

- uneven numbered .NET release are STS versions
  (e.g. dotnet7)

- Every .NET LTS release (even numbered release) will be
  generally available in an odd numbered year (e.g. dotnet8
  in Nov 2023). Therefore a .NET LTS release needs to be
  supported on Ubuntu LTS from one year ago (22.04), from the
  next year (24.04) and the one after that (26.04), with a
  clear indication of the MS end of support date in the
  package itself.

- At the EoL of the .Net release, both STS and LTS, we will
  remove the package from the archive (by providing a
  transitional package that uninstalls all binaries).

- We will not MIR .NET STS versions (e.g. dotnet7);
  see also https://bugs.launchpad.net/ubuntu/+source/dotnet7/+bug/2023530/comments/2.

TL;DR: dotnet6 and dotnet8 needed for >= 22.04