Microsoft released ASP.NET Core in 2016 and is the signature component of the .NET 5 platform. The extension package can now run on Windows, Linux, and macOS computers, and licensing fees have largely been removed. The move to open-source terms expands the definition of a Windows host and supports modern app programming methods. Essentially, ASP.NET Core is the open-source and cross-platform version of ASP.NET. All new ASP.NET development should happen in .NET Core to take advantage of all new updates. Older, Windows-only versions of ASP.NET will continue to receive minor updates and bug fixes, but the majority of innovation will happen with ASP.NET Core. Web hosting companies still frequently support older versions of ASP.NET, so be sure to host your application with a provider that runs ASP.NET 5 or higher. The ASP.NET Core runtime extension includes many module options to accelerate web development for professional teams or individual programmers. The broader .NET 5 includes the best of .NET Core.NET Framework, Xamarin, and Mono for wider support than just Microsoft SQL Server.