What is the motivation to change from netstandard2.0 to netstandard2.1?

[Karql]

@lbargaoanu What is the motivation to change from netstandard2.0 to netstandard2.1?
In this commit: 7930dd3

We have common libraries used by apps in NET6 and also large project in NET Framework.
Now we have to multitarget those libraries if we want to use latest version of AutoMapper.

[jbogard]

I don't use full .NET anymore and haven't for many years now.

[jbogard]

The problem is if we target .NET Standard 2.0, we'll also get asked to target .NET 4.6.1 because of the problems called out in that. We already had to do that once, add the net461 target. That's really hard to avoid if you target only netstandard2.0. There's no netstandard2.0.1 that only targets net472 and above.

[Karql]

Yes I understand it but as I said you can only targeting netstandard2.0 and mark it in documentation or other place that NET Framework >= 4.7.2 is required.

Exactly the same has been done in e.g. EF Core 3.

They changed to netstandard2.1 in 3.0 version. There was a big feedback there is too soon etc. Then in 3.1 they reverted to netstandard2.0.
dotnet/efcore#18141 (comment)

IMO considering case with net461 that you described it is much better to target netstandard2.0 and let AutoMapper to work with NET Framework >= 4.7.2 than drop support at all.

Best regards,
Mateusz

[jbogard]

Yes but EF Core 5.0 does not. I don't use .NET 4.x. I have no need or reason to support it. Neither do any of my clients that use AutoMapper. I don't want to even test on 4.7.2.

If a client or sponsor wanted to pay for supporting 4.7.2 then fine, I'd support it. Otherwise I don't have any need for it.

[martyt]

Removing .NET Standard 2.0 support from AutoMapper is going to have a cascading negative effect that you may not have considered

For example, we have a .NET 6 application that uses IdentityServer4.EntityFramework.Storage (among other Identity Server 4 packages), which still targets .NET Standard 2.0, hasn't been updated in a year or so and may not be anytime soon (because the code is stable). That NuGet package also depends on AutoMapper but - as you can guess - since the package targets .NET Standard 2.0, users of that package are precluded from upgrading to AutoMapper 11 even though we don't have a .NET Framework application anywhere in sight.

In my experience, adoption of .NET Standard 2.1 isn't terribly widespread; .NET Standard 2.0, however is broadly used.

If there's no harm (and I don't think there is) in adding a .NET Standard 2.0 target to AutoMapper, I really wish you'd consider it. Otherwise there are going to be lots of people who will be stuck at 10.1.1 forever.

[jbogard]

Identity Server 4 support ends November 2022. Its successor, Duende.IdentityServer, targets net6.0 exclusively.

If folks want a version that targets full .NET, they can use 10.1.1.

If I targeted .NET Standard 2.0, I'd have to have a big red warning label "only .NET 4.7.2 and later". Which I'd rather not, I already went that path and it was problematic enough we added the net461 target.