Which Microsoft.Extensions.* version to target depending on target framework

[verdie-g]

In my company, we only upgrade Microsoft.Extensions.* nugets when we upgrade .NET, e.g., we use .NET 8 so we only target Microsoft.Extensions.* version 8.*.

We aren't really sure we do that anymore. Is it safe to target ME* nugets version 9 or 10 from .NET 6 or 8? I see that MEAI targets different versions depending on the target framework.

[stephentoub]

What problem are you trying to solve? Why do you constrain the version of nuget package based on your TFM?

[verdie-g]

Why do you constrain the version of nuget package based on your TFM?

Because that was done historically in the company and we are trying to figure out if there is any reason to do that. I think I've seen several MS nugets doing something like that (e.g. the linked MEAI nuget).

[KalleOlaviNiemitalo]

According to .NET Platform Extensions Support Policy, Microsoft.Extensions.* version 8 packages built from this dotnet/extensions repository are already out of support. So if you want a supported version, you should be using 9.10, which was released yesterday.

That however does not apply to packages that are built from the dotnet/runtime repository, such as Microsoft.Extensions.DependencyInjection. For those, there used to be a reason to stay with version 8 of the packages when targeting .NET 8, because the support for version 9 STS would have ended on May 12, 2026 but support for version 8 LTS would have continued longer and ended on November 10, 2026. That was changed a month ago and now both will be supported until November 2026, so the end-of-support date is no longer a reason not to upgrade to version 9 of the packages.