Feature 'interpolated strings' is not available in C# 5. Please use language version 6 or greater

Question

There is a similar question to this here but I believe that involves a different cause.

I moved a class from a newer project into an older project. Both were targeti

Answer 1

(It can applicable VS 2019 - .NET Framework 4.8 Web Application projects easily)

I have realized this issue after install DotNetCompilerPlatform v3.6

I have looked for TheColonel26's answer but I couldn't change selected language version:

Appearantly, we can not change selected language version. (For details look here)

After that I have used kfwbird's answer but with changes for newer version:

Now it works as should be.