.NET 9

This interim non-LTS version has served its purpose: we road-tested the new features on it, and with ten out we're wrapping it up. Considering it abandoned — projects jump straight from .NET 8 to .NET 10.

.NET 9 — not an LTS, but we tried it on one new project. What I liked:

• new LINQ methods: CountBy, AggregateBy, Index — genuinely handy
• JSON serialization improvements
• Task.WhenEach — a small thing, but a nice one

The version is solid, but it's not LTS — strategically it makes more sense to already be looking at .NET 10.