.NET 8 and .NET 9 End of Support on 10 November 2026: What Businesses Running C# Apps Should Do

Published: 30 October 2026 · By فؤاد الحرازي · Editorial policy

In less than two weeks, on 10 November 2026, Microsoft ends support for both .NET 8 and .NET 9, as the .NET team announced on the official Microsoft .NET blog. It sounds purely technical, but it affects many Saudi businesses that run an in-house application written in C#: a customer portal, an integration service between systems, a reporting tool, or a small program a developer wrote years ago that quietly runs on a server. This article explains what actually changes and the practical plan before and after the date.

What exactly did Microsoft announce?

Why do both end on the same day? Microsoft extended STS support from 18 to 24 months, so .NET 9 now ends alongside .NET 8. The blog notes that 10 November is a Patch Tuesday, and a final update may ship that day for either version if there is a known critical issue. Note that Microsoft’s 2026 end-of-support page still lists an earlier date for .NET 9 (12 May 2026), from before the STS extension; the more recent reference is the .NET team’s announcement.

What does end of support mean in practice?

• Apps keep running: nothing stops working on 10 November.
• No new security updates: any vulnerability found after that date stays open on these versions.
• No technical support from Microsoft for these versions.
• Visual Studio: the blog says a future Visual Studio 2022 servicing update will mark the .NET 8 and 9 components as out of support, with an option to remove them.

The real risk is not day one, but the months that follow: an internet-facing app that reads customer or invoice data, running on a runtime that will never be patched again.

A five-step plan

1. Inventory: ask your team or vendor for a list of every in-house application and the .NET version it runs on. Check project files (TargetFramework) and the servers hosting them.
2. Rank by risk: internet-facing apps first, then those handling financial or personal data, then internal tools.
3. Upgrade to .NET 10: Microsoft recommends retargeting to net10.0 and updating development and hosting environments, after reviewing the .NET 10 breaking-changes list.
4. Test: run tests on a staging copy and confirm third-party NuGet packages are compatible with .NET 10.
5. Retire instead of upgrading: some apps are not worth upgrading because your core system already does the job. This is the moment to drop them.

Questions to ask your vendor or developer

• Which .NET version does each of our applications run on, and is anything still on a version older than .NET 8?
• Which third-party packages does each app depend on, and do they have .NET 10-compatible versions?
• How many working days will upgrading and testing take, and who pays for it?
• Does the business hold the source code and deployment documentation, or does only one person have them?
• After the upgrade, what is the monthly patching plan until .NET 10 support ends in November 2028?

If the answer to the fourth question is “we don’t know”, the problem is bigger than a .NET version, and it deserves a management decision, not only a technical one.

The bigger lesson: every side system has a lifecycle

Many businesses build a layer of small programs around their accounting system: one tool to load data from Excel, another to send invoices on WhatsApp, a third to pull attendance records, a fourth to connect to Fatoora. Each needs maintenance, upgrades and a developer who understands it. The end of .NET 8 and 9 exposes that whole layer at once. The question worth asking now: how many of these programs could you drop if the function were part of the ERP itself?

How Riv-ERP reduces side systems

Functions that are often built as separate programs are already inside Riv-ERP:

• Excel data upload: Riv-ERP Cloud uploads items, customers, suppliers, employees, departments, general journals, inventory adjustments and payroll; RivDesktop has an import screen that reads xls, xlsx and xlsm files with column mapping.
• E-invoicing: Fatoora integration is built into both editions.
• Attendance devices: attendance device integration in both editions, and ZKTeco BioTime integration in RivDesktop.
• Sending documents: RivDesktop sends invoices, vouchers and statements as PDF via WhatsApp and email; Riv-ERP Cloud has WhatsApp alerts.
• Reports and dashboards: 360 dashboards in the cloud edition, and a no-code form and report designer in RivDesktop.

And if you would rather not manage any runtime on your own servers, Riv-ERP Cloud runs in the browser on Oracle Cloud servers with nothing to install. Details in the Riv-ERP Cloud guide; to compare with the desktop edition, read the edition comparison.

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