.NET Core 3.0 'Dies' March 3

Microsoft advised developers that .NET Core 3.0, a major milestone in the new cross-platform, open-source direction of .NET, will reach "end of life" on Tuesday, March 3.
Coders who haven't already are advised to switch to .NET Core 3.1, a long-term support (LTS) edition released three months ago that will "live" (be supported) for at least three years.
The "end of life" of a release means it won't be included in future .NET Core patch updates.
Though it only "lived" for about five months, .NET Core 3.0 was an important milestone for Microsoft's transition from the aging, Windows-only .NET Framework to .NET Core. because it introduced support for Windows Presentation Foundation (WPF) and Windows Forms desktop development, one of the more problematic areas of the transition.
The Microsoft support policy explains the difference between LTS and "Current" releases:
  • LTS releases include features and components that have been stabilized, requiring few updates over a longer support release lifetime. These releases are a good choice for hosting applications that you do not intend to update often.
  • Current releases include features and components that are new and may undergo future change based on feedback. These releases are a good choice for applications in active development, giving you access to the latest features and improvements. You need to upgrade to later .NET Core releases more often to stay in support.
"Both types of releases receive critical fixes throughout their lifecycle, for security, reliability, or to add support for new operating system versions," Microsoft said in a Feb. 28 post that explains how to migrate to .NET Core 3.1. "You must stay up-to-date with the latest patches to qualify for support."
Though Microsoft is advising developers to migrate to .NET Core 3.1, that release itself is a transition to the unifying .NET 5 coming in November that will wrap up everything in one package.