Sync .NET version with C# version

[ekolis]

It's confusing that that C# language version is always four versions ahead of the .NET runtime/SDK version. It's easy to conflate the two, so if you say ".NET 10", you might actually mean "C# 10", which actually runs on .NET 6. Or you might say "C# 10" but actually mean ".NET 10", which uses C# 14. It would be nice if these numbers could be brought in sync, since C# and .NET are developed in parallel on the same release schedule. In the past, this wouldn't have made sense, since VB had its own version number separate from C#, but now that VB is pretty much deprecated, it might make sense to do this. So we'd then skip ahead four versions of .NET at some point to keep up with C#, e.g. renaming .NET 11 to .NET 15, or .NET 12 to .NET 16. Of course there is also F#, but it seems to be versioned parallel to .NET, so it could be increased by four as well.

[arledesma]

I'm not sure that the alignment of version numbers actually addresses the confusion that you are talking about, but it instead becomes a forcing change.

If we are proposing a change to version numbers then why not just go with calver?

C# 2026.x (YYYY.MINOR)
.NET SDK 2026.10.x (YYYY.M.FEATPATCH) where FEATPATCH == (100 * FeatureBand + Patch) because VS
.NET Runtime 2026.10.x (YYYY.M.PATCH)

We'll still have people referencing dotnet as the language. We'll still have people confused when there is a breaking change within the same major. We'll still have people wondering why there were no breaking changes (that affected them) with a major bump. None of it matters.