Our company has multiple applications that are .Net Framework 4.8 and we also are growing the number of applications that are .Net Core 3.1.
We have written a whole library of NuGet packages (in a private repository) written in .Net STANDARD 2.0 that are currently consumed by both the 4.8 and Core 3.1 applications mentioned above.
Standard 2.1 offers many new language features, such as Nullables, and we want to start to migrating our NuGet packages over to Standard 2.1, but obviously need to continue to support those applications still on .Net 4.8 (which can't consume Standard 2.1).
Obviously we need to branch our source code, but what is the convention for publishing two almost identical NuGet packages, one written in 2.0 and the other 2.1?