But you can still write C# 1.0 compatible code and it will run ok. Just don't look at the new features. They added quite a bit of low-level performance related

But you can still write C# 1.0 compatible code and it will run ok. Just don't look at the new features. They added quite a bit of low-level performance related features recently, like span, ref, template math, readonly struct, vectors etc, which are quite useful for the performance minded, but can be safely ignored by the CRUD crowd.