.NET 8 and .NET 9 end of support: November 10, 2026, as .NET 11 launches

Microsoft ends support for both .NET 8 and .NET 9 on Tuesday, November 10, 2026, according to its official .NET support policy. Microsoft's event listing says .NET Conf 2026 opens online that day with the official release of .NET 11. Teams on either version should plan a move to .NET 10, the long-term support (LTS) release covered until November 14, 2028, or to .NET 11.

Key dates

• .NET 8 (LTS): released November 14, 2023; support ends November 10, 2026.
• .NET 9 (STS): released November 12, 2024; support ends November 10, 2026.
• .NET 10 (LTS): released November 11, 2025; supported until November 14, 2028.
• .NET 11 (STS): expected November 10, 2026, per the .NET Conf schedule. Release Candidate 3, listed by Microsoft as a go-live build, has been out since October 25, 2026.
• .NET Conf 2026: November 10 to 13, online, 8:00 a.m. to 5:00 p.m. PST each day (11:00 a.m. to 8:00 p.m. EST; 16:00 UTC to 01:00 UTC the next day).

Why two versions expire on the same day

.NET 8 is an LTS release, and LTS versions get three years of free support. .NET 9 is a standard term support (STS) release. STS versions used to get 18 months, which would have ended .NET 9 on May 12, 2026, but a change announced on September 16, 2025 extended STS support to 24 months starting with .NET 9, moving its cutoff to November 10. Since .NET Core 3.1, end-of-support dates have been set on Patch Tuesday, the second Tuesday of the month.

What end of support means

Nothing switches off on November 10: installed runtimes and deployed apps keep running. What stops is servicing. Microsoft no longer provides fixes, updates or online technical assistance, and its policy strongly recommends against running out-of-support software. Container images for unsupported versions can still be pulled but get no further updates, under Microsoft's container tag policy.

Until the cutoff, support requires the latest patch. At the time of writing, that means 8.0.33 and 9.0.22, released out of band on October 25 to fix a Brotli decompression buffer overflow (CVE-2026-111497) and other flaws, according to the .NET blog. Self-contained apps must be rebuilt and republished to pick up a patched runtime.

.NET 10 or .NET 11?

.NET 10 is the lower-risk target: the current LTS release, supported until November 14, 2028. For most .NET 8 projects, the move starts with changing the target framework to net10.0 and reviewing the breaking changes in .NET 10.

.NET 11 is an STS release. Microsoft has not yet published its end date, but the two-year STS term points to November 2028, close to the end of .NET 10, so the choice is about features and upgrade risk more than support length.

Check hardware first. .NET 11 raises the x86/x64 baseline from x86-64-v1 to x86-64-v2 and requires the LSE instruction set on Windows Arm64. Microsoft's runtime notes say it fails to run on older processors, though the affected x86/x64 chips left vendor support around 2013. To list what a machine has installed, run dotnet --list-runtimes and dotnet --list-sdks, as Microsoft's install guide describes.

What's new in .NET 11 and C# 15

C# 15 is the default language version for projects that target net11.0. Microsoft's C# 15 notes list:

• Union types: declared with the new union keyword, a union holds one of several case types, and the compiler checks that switch expressions cover every case.
• Closed hierarchies: the closed modifier limits derivation to the declaring assembly, so pattern matching over subclasses can be exhaustive.
• Extension indexers, labeled break and continue and collection expression arguments.
• Memory safety rules, still a preview feature.

The .NET 11 overview adds Zstandard compression, IEEE 754 decimal types (Decimal32, Decimal64 and Decimal128), union support in System.Text.Json, a LINQ FullJoin method and #:include for splitting file-based apps across files. Runtime Async, which moves async handling from compiler-generated state machines into the runtime, is an opt-in preview.

How to watch .NET Conf 2026

Microsoft's Reactor series page lists all four days as livestreams, each from 8:00 a.m. to 5:00 p.m. PST (16:00 to 01:00 UTC):

• November 10 and 11: product team days with the .NET and Azure teams; day one opens with the .NET 11 release.
• November 12 and 13: community days with open-source project leaders, .NET partners, .NET Foundation leaders and MVPs.

The official site, dotnetconf.net, has the full agenda. Last year's sessions went up as YouTube playlists, linked from Microsoft's .NET 10 announcement. For more, see our Conferences coverage and the Developers section, which also tracks Node.js 26 becoming LTS.

Frequently asked questions

When does .NET 8 support end?

On November 10, 2026. .NET 8 shipped on November 14, 2023 as an LTS release with three years of support.

Was .NET 9 support extended?

Yes, from May 12, 2026 to November 10, 2026, when Microsoft lengthened STS support from 18 to 24 months.

What is the .NET 11 release date?

Microsoft's .NET Conf page says the event opens on November 10, 2026 with the release of .NET 11, and its documentation says general availability is expected in November 2026.

Will .NET 8 apps stop working after November 10?

No. They keep running but get no further security fixes or Microsoft support.