Repos Still on .NET 8 Need More Than a TFM Change Before November 10 Support Cutoff

Both .NET 8 and .NET 9 reach end of support on November 10, 2026, after which security patches stop, and the in-process model for Azure Functions retires on the same date. Nothing breaks immediately, but newly discovered vulnerabilities would remain unpatched. .NET 10, an LTS release supported until November 2028, is the natural upgrade target. The article notes that the target framework is often not set in a single project file, since it may come from Directory.Build.props properties, global.json SDK pins, Docker base images, or CI pipeline SDK settings. It also flags pitfalls such as the Ubuntu-based default image tags, the changed default container port, and dropped zlib in .NET 9 images.