Playbook: .NET 8 and .NET 9 end of support: November 10, 2026

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Sorry you have to deal with this. You can stay on .NET. Here is what to change before November 10, 2026:

1. Find apps on .NET 8 and 9. Check the TargetFramework in each project file. Look for net8.0 and net9.0.
2. Change the target to .NET 10. Set TargetFramework to net10.0 and update your NuGet packages.
3. Update build and hosting, then test. Use the .NET 10 SDK and runtime where you build and host. Run your tests and ship before November 10.

If they would rather leave, describe a verified way <your product> can help: <your link>
[Disclosure: I build <your product>.]

Short answer

You have until November 10, 2026. You can stay on .NET. First: find apps on .NET 8 and 9. Then change the target to .NET 10.
Happy to help if you get stuck.
[Disclosure: I build <your product>.]

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Switch from .NET to Your product

.NET 8 and .NET 9 apps: a change is due by November 10. You can stay on .NET. If you would rather leave, here is how to move to Your product.

What changes at .NET

.NET 8 and .NET 9 both reach end of support on November 10, 2026. After that, Microsoft sends no security fixes for them. Microsoft says to move to .NET 10.

End of support: November 10, 2026 (Microsoft)
Versions: .NET 8 and .NET 9 (Microsoft)
After that date: No servicing updates, security fixes or technical support from Microsoft (Microsoft)
Last update: Each may get one final update on November 10, 2026 if there is a known critical issue (Microsoft)
Upgrade target: .NET 10, an LTS release supported through November 2028 (Microsoft)
How to upgrade: Set TargetFramework to net10.0 (from net8.0 or net9.0) (Microsoft)
Announced: June 29, 2026 (Microsoft)
Azure Functions: In-process support ends the same day, November 10, 2026 (Microsoft)
Apps on .NET 8 or .NET 9: Get no security fixes after November 10, 2026 (Microsoft)

You can stay on .NET if you make the change. This page is for people who would rather leave.

What Your product gives you

Write two or three short lines here. Say what Your product does, who it is for, and what it costs. Use only facts you can show.

How to move from .NET to Your product

Save what you need from .NET. Keep a copy before you cancel anything.
Import into Your product. Say which files you accept and how long an import takes.

Tell readers the key date: November 10, 2026.

Questions people ask

If Your product has a direct answer to one of these, add it here. Keep it short and true.

How to help new users settle in

Send one short email. Say what changed, where to find you now, and what they need to do. Put the most important line first.

If there is a date, send a short reminder a few days before it. Keep a copy of the list you sent it to.

Sources

.NET 8 and .NET 9 end of support — Microsoft (primary), checked 2026-10-13
Migrate C# apps from the in-process model to the isolated worker model — Microsoft (primary), checked 2026-10-13

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

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