In a crucial reminder to the developer community, Microsoft has officially ended support for .NET Core versions 3.1 and earlier. The change, which took effect on December 3, 2022, means that users of these versions must upgrade to stay secure. Failing to do so exposes their applications to security vulnerabilities, as Microsoft will no longer provide bug fixes, patches, or security updates for outdated versions.
The end-of-life (EOL) for .NET Core 3.1, originally announced in 2021, aligns with Microsoft’s support lifecycle policy, which typically guarantees three years of long-term support (LTS). Since its launch in December 2019, .NET Core 3.1 was a widely adopted framework for developing cross-platform applications. However, Microsoft has now shifted its focus toward newer releases, such as .NET 6 and .NET 8.
.NET 6, which was released in November 2021, is currently supported as the long-term stable version, while .NET 8 is expected to receive similar treatment, making it a safer option for developers looking to future-proof their tech stack.
Running software on unsupported frameworks is a significant cybersecurity risk. Attackers frequently target vulnerabilities in legacy platforms that are no longer updated. Key risks include: