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Microsoft's materials give November 10, 2026 as the end-of-support date for .NET 8 (LTS) and .NET 9 (STS), the day .NET 11 shipped; its releases table lists November 14, 2028 for both .NET 10 (LTS) and .NET 11 (STS).

Microsoft's out-of-band .NET release fixes CVE-2026-111497 in Brotli decompression and a Linux tarball ownership flaw, and re-releases two advisories the October 13 release did not fully address.

Microsoft's first .NET 11 release candidate ships with a go-live support license and locks in C# 15's union types, closed hierarchies, and four other preview-era language features as stable defaults.

The June 9 .NET 11 Preview 5 brings a closed class modifier for exhaustive switch checking and with(...) collection expression arguments, alongside the first runtime scaffolding for C# union types.

Microsoft's third .NET 11 preview brings the first in-SDK drop of C# 15 union types, Zstandard support in ASP.NET Core, and cryptographically signed container images.