.NET Framework Frequently Asked Questions

What is the .NET Framework?

The .NET Framework is a software development platform from Microsoft that provides a large library and runtime environment for building, deploying, and running Windows applications.

Which versions of .NET Framework are still supported?

As of 2025, .NET Framework 4.8 and later are the only actively supported versions for security updates. Earlier releases are in extended support only for certain Windows updates.

Can I run .NET Framework apps on Linux or macOS?

Directly, no. The .NET Framework is Windows‑only. For cross‑platform development, use .NET (formerly .NET Core) which runs on Windows, Linux, and macOS.

How do I migrate a .NET Framework application to .NET 8?

Use the Migration Guide and the try-convert tool. Review API compatibility, update NuGet packages, and test thoroughly on the target runtime.

Where can I find performance tuning best practices?

See the Performance and diagnostics documentation for profiling, GC tuning, and code optimization techniques.

What security features does the .NET Framework provide?

It includes Code Access Security (CAS), role‑based security, data protection APIs, and built‑in validation for web applications (ASP.NET request validation).

How can I report a bug or request a feature?

Use the Microsoft Developer Community to file issues. For security concerns, see the Security reporting guidelines.