.NET 10 migration audit
.NET 8 and .NET 9 will be out of support from 10 November 2026. Nicolas Cousin's Migration audit (€5,500 net, 6 days) inventories the blocking dependencies and APIs, estimates the effort per module and delivers a roadmap to move to .NET 10 in batches.
Updated on 6 November 2026
Why migrate now
- .NET 8 and .NET 9: no more security patches from 9 November 2026.
- .NET Core 3.1, .NET 5, 6 and 7: out of support for several years.
- .NET Framework 4.6.1 and earlier: out of support since 26 April 2022. .NET Framework 4.6.2 is supported until 12 January 2027. .NET Framework 4.8 and 4.8.1 remain supported as long as the Windows version they are installed on is.
- .NET 10 is the current long-term support (LTS) version, supported until 14 November 2028.
Microsoft .NET support policy (checked on 5 November 2026)
What the Migration audit includes
- The whole Complete audit: measurements, A to E grades, PDF report, findings register, action plan.
- An inventory of the dependencies and APIs that block the migration (NuGet packages, abandoned libraries, Windows APIs).
- An estimate of the effort per module.
- A migration roadmap in batches, so you can migrate without stopping new development.
Price
€5,500 net, 6 days, up to 100,000 lines.
50% on order, 50% on delivery. VAT not applicable.
Common pitfalls
- Authentication libraries that were retired or became paid.
- NuGet packages with no compatible version.
- Code tied to Windows or IIS (server-side WCF, Web Forms, System.Web).
- Missing tests, which make every step risky.
An example coming soon
A public Migration audit of NorthwindTraders (an open source ASP.NET Core 3.0 application, to .NET 10) is in preparation. In the meantime, here is an example of a Flash audit: the Bonobo Git Server case study.
Frequently asked questions
Do we need to go through .NET 9?
No, we aim directly for .NET 10, the long-term support version.
Do you do the migration?
Yes, after the audit, as support for your team or as a Tech Lead assignment.
Does my application need to build?
It is better if it does. Otherwise, the audit is still possible with static analysis only.