.NET 8 and .NET 9 both reach end of support on November 10, 2026. After that date, Microsoft stops releasing security fixes for either. Applications built on them keep running, but any vulnerability discovered later stays open. The upgrade target is .NET 10, a long-term support release supported to November 2028. Many custom web applications, portals, and APIs in universities and agencies run on .NET 8, so this deadline matters even if the operating system underneath is current.
.NET versus .NET Framework
| Platform | Support model |
|---|---|
| .NET (5, 6, 7, 8, 9, 10...) | Each release has its own end date: long-term support (LTS) releases for three years, standard-term (STS) releases for two |
| .NET Framework 4.8 and 4.8.1 | Supported as part of the Windows version it runs on; no separate end date while that Windows version is supported |
| Older .NET Framework versions | Many are out of support; applications should run on 4.8.x |
The November 10 date applies to modern .NET 8 and 9, not to .NET Framework.
Find which runtimes you use
dotnet --list-runtimes
dotnet --list-sdksOn each server, these list installed runtimes. Installed is not the same as used: check each application's project files or its deployment notes for its target framework (for example net8.0), and remember applications that ship as self-contained, which include their own runtime and must be rebuilt to update it.
Upgrading an application
- Change the target framework to
net10.0and update NuGet packages to versions that support it. - Review Microsoft's breaking-change notes for each version you skip.
- Build and run the test suite; fix compile errors and warnings.
- Deploy to a test environment with the .NET 10 runtime installed.
- Test sign-in, data access, file handling, and integrations.
- Deploy to production, keeping the previous build ready to roll back.
Moving from .NET 8 to .NET 10 is usually a modest change for well-maintained applications. Applications with outdated third-party packages or no tests take longer, and those are the ones to start first.
Hosting on IIS
IIS needs the ASP.NET Core Hosting Bundle for the runtime version an application uses. Install the .NET 10 hosting bundle before deploying upgraded applications, and keep the older bundle until every application on the server has moved. Restart IIS after installing a bundle. In the cloud, App Service and container images need their runtime or base image updated too.
Common questions
Who upgrades the application? The code belongs to whoever owns it, your developers or vendor; the host installs runtimes and deploys; see shared responsibility on AWS.
Can we skip .NET 9? Yes; go straight from 8 to 10.
What if a vendor application is on .NET 8? Ask the vendor for a .NET 10 release and a date.
Do security fixes still come monthly? Yes, for supported versions, on Patch Tuesday; see Patch Tuesday.
What about .NET 6 or 7? Already out of support; upgrade those first.
A short timeline to November 10
| When | What |
|---|---|
| Now | List every .NET 8 and 9 application, its owner, and its test coverage |
| Next two weeks | Install .NET 10 runtimes on test servers; upgrade and test the simplest applications |
| Before November 10 | Deploy upgraded applications to production; agree dates for any that cannot make it |
Applications that cannot be upgraded in time should be listed with a date and kept on fully patched servers with restricted exposure meanwhile.
Do we lose anything moving to .NET 10? Usually only deprecated features flagged in the breaking-change notes, which the build warns about.
Do we need to update Visual Studio? Developers need a version that supports .NET 10 to build upgraded applications.
What about Azure Functions or AWS Lambda written in .NET? Their runtimes have their own support schedules tied to .NET versions; update them too, and check the platform's supported runtime list.
Will performance change? Each .NET release typically improves performance; measure key pages before and after.
Is .NET 10 the last upgrade for a while? Until November 2028; plan the next LTS move well before then, ideally as part of normal maintenance rather than another deadline project.
How eWay handles .NET hosting
On servers eWay manages, eWay installs and patches .NET runtimes and hosting bundles, keeps the versions your applications need, and deploys upgraded applications through the release pipeline with a tested rollback. Releases pass functional tests in staging before production. Your developers or vendor own the application code and its upgrade.
What to include in a support ticket
- The applications, their current .NET version, and who maintains the code
- When an upgraded build will be ready for testing
eWay customers can open a ticket in the support portal or email support@ewaycorp.com.
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