.NET 8 support ends on 10 November.
Planning a .NET Framework to .NET 8 migration? Aim for .NET 10 instead: .NET 8 and .NET 9 both lose support on 10 November 2026; apps keep running, but without security patches. For most, moving to .NET 10 is mainly a target framework change and a review of breaking changes. VB6, Access and older .NET Framework apps are bigger jobs, and that's where QServices plans the move app by app.
Microsoft lists the technologies that don't exist in current .NET. Each one needs a replacement, and that, not line count, decides the effort.
| Technology | Status in current .NET | Replacement |
|---|---|---|
| AppDomains | Not available | Separate processes or AssemblyLoadContext |
| Remoting | Not available | gRPC or HTTP APIs |
| WCF server | Not in .NET itself | CoreWCF for HTTP and NetTcp (not MSMQ); gRPC for new work |
| Web Forms | Not available | Blazor or Razor Pages; often no need to move every page |
| Code Access Security | Not available | Operating system and container security |
| Windows-only APIs | Mostly via the Windows Compatibility Pack | About 20,000 APIs restored |
| COM+ and Workflow Foundation | Not available | Rebuild on current services |
From Microsoft Learn's porting documentation, October 2026.
In a 950,000-line VB6 migration Microsoft documented, converting code was well under half of the work.
| Work | Hours | Share |
|---|---|---|
| Code conversion | About 3,650 | About 44% |
| Review and refactoring | 3,400 | About 41% |
| Testing | 1,300 | About 16% |
From an archived Microsoft VB6 migration case (8,350 hours in total). Vendor tools that convert code faster help with the first row only.
Access tops out at 2 GB and 255 users. There are three ways off it.
| Option | What you get | Watch for |
|---|---|---|
| Move the data to SQL, keep the forms | SQL Server Migration Assistant moves tables and links the existing front end | Slow queries and stored SQL passwords; a stopgap, not an end state |
| Rebuild in Power Apps | Dataverse or Azure SQL behind a modern app, with approvals | Licensing; 10 GB of Dataverse storage per base licence |
| Rebuild as a web app | ASP.NET Core or Blazor on Azure SQL | More build time, most flexibility |
On 10 November 2026, the same day as .NET 9. Apps keep running but get no patches. Move to .NET 10, supported until 14 November 2028; for most apps it's a target framework change plus a breaking-change review.
Microsoft has deprecated it in favour of GitHub Copilot's modernization chat agent, which handles .NET Framework to current .NET and Web Forms to Blazor scenarios. It speeds up mechanical work; design, testing and unavailable technologies still need people.
It depends far more on testing, refactoring and business rules than on lines of code. In a Microsoft-documented case, code conversion was about 44% of the hours. We price after inventorying the app.
Runtimes, third-party packages, unavailable technologies such as AppDomains, Remoting or WCF servers, test coverage and a rollback plan.
Move the data to SQL with SQL Server Migration Assistant as a stopgap, then rebuild the front end in Power Apps or as a web app.
Ask how they handle the unavailable technologies, how they test, whether they retarget before rewriting, and what they've moved before.
Facts on this page checked on 22 October 2026.
Founder and CEO
Chief Sales Officer
Join our live webinar on Sept 24 and see five
ways to automate meetings, approvals, and
document search with tools already in your
tenant.
