.NET 9 continued the annual release cadence after .NET 8 LTSLong-term support — a release branch maintained with security fixes for years, common in Linux and Node.: faster JITJust-in-time compilation — translating code to machine instructions at runtime instead of ahead of time. and GC, improved ASP.NETMicrosoft's framework for building web applications and APIs on the .NET platform. Core, and Tensor primitives for ML workloads. TeamsMicrosoft Teams — chat, video calls, and Office integration for workplace collaboration. use it for greenfield apps while .NET 8 remains the supported LTSLong-term support — a release branch maintained with security fixes for years, common in Linux and Node. choice through 2026.

.NET 9 kept the platform current between LTSLong-term support — a release branch maintained with security fixes for years, common in Linux and Node. releases with AI and cloud focus.

Built-in tensor types signaled .NET's push into on-device and server AI inferenceRunning a trained model to produce predictions — as opposed to the training phase that learns weights..