Business Central is transitioning to .NET 10

 

The short version

Microsoft is moving supported Business Central releases from .NET 8 to .NET 10, online and on-premises.

If you are online, Microsoft does this for you

For Business Central online, the transition is handled under the hood. Microsoft migrates the environment during its configured maintenance window, so the only lever you really have is making sure that window sits somewhere sensible for your business.

On-premises: the CU decides the runtime, not the major version

This is the part I would put on a sticky note. For on-prem, .NET 10 arrives through cumulative updates to supported releases. BC 27 picks it up at CU 27.12. BC 28 picks it up at CU 28.6. Both of those shipped in October 2026. BC 29 is on .NET 10 from release.

28.5 and 28.6 want different things.

BC release	CU	Runtime	AL / VS Code extension
BC 27	27.12	.NET 10	16.10.x
BC 27	27.11 and earlier	.NET 8	16.4.x
BC 28	28.6	.NET 10	17.10.x
BC 28	28.5 and earlier	.NET 8	17.0.x
BC 29	Release	.NET 10	18.1.x

 

What changes on your dev machine

The AL Language extension needs .NET 10 too, and Microsoft changed how it gets it. Starting with 2026 release wave 2, the extension uses the .NET Install Tool for Visual Studio Code to acquire the .NET 10.0 runtime. VS Code downloads and installs it automatically when the extension starts. On a normal laptop with open internet, you will not notice.

Extensions and .NET interop: who actually has exposure

If you are cloud only and your extensions are pure AL, you have no exposure. DotNet interop has not been available for cloud extensions for years, which is exactly why this change is a non-event for most AppSource and per-tenant code.

The people who should look harder:

• On-prem solutions that still carry DotNet declarations against custom or third party assemblies. Those assemblies were built against a target framework. Confirm they load under .NET 10 before you apply 27.12 or 28.6.