Add .NET 10 support information

[richlander]

We are building up infra for .NET 10. We need to know what the min supported version is for each OS/distro.

Please comment if these versions should change, now or in the future. I've made some initial changes w/rt to .NET 8 and 9. It's all open for discussion. Note that the versions should be based on what makes sense to support as of late 2025 not late 2024 (now).

Compare with:

• https://github.com/dotnet/core/blob/main/release-notes/8.0/supported-os.md
• https://github.com/dotnet/core/blob/main/release-notes/9.0/supported-os.md

Note: We're moving to two digits (before the .). I'm sure that will break someone's assumptions in their code.

Related: dotnet/runtime#109939

@Falco20019 @leecow @rbhanda

[matouskozak]

The mobile side LGTM!

The only change from .NET 9 looks to be the cut of iOS 15 support which should be already out of support. @dalexsoto do you know if we should expect iOS 16 to get OOF by late 2025?

@jonpryor is there anything from Android side that we should change?

[dalexsoto]

The only change from .NET 9 looks to be the cut of iOS 15 support which should be already out of support. @dalexsoto do you know if we should expect iOS 16 to get OOF by late 2025?

@matouskozak I think it is okay to keep as of today, we can remove later in the previews if needed which I think is unlikely.

[richlander]

I can removed iOS 15 from earlier releases as a separate PR. Good call.

Thanks for the review!

[Falco20019]

@richlander My PR #9641 would already remove them. Should I do some more adjustments there or is it ready for merging?

[richlander]

@Falco20019 -- I added Azure Linux to the .NET 10 JSON. It broke our tool a bit because I don't have a lifecycle to point to. I hand edited the MD to accommodate that.

I still want to get your PRs on the tool merged so that we can be back to sharing source. Sorry about that! Perhaps we can resolve that later this week or next.

[Falco20019]

@richlander Just out of curiosity: .NET 11 (expected ~Nov 10th 2026) is going to drop Windows Server 2012 (+R2) since ESU is expected to end in October 2026, right?

A bit off-topic: https://learn.microsoft.com/en-us/lifecycle/faq/extended-security-updates#esu-availability-and-end-dates lists Windows 10 ESU start as November 11, 2025 while https://learn.microsoft.com/en-us/lifecycle/products/windows-10-enterprise-and-education lists October 14, 2025 as EOS. According to the yearly ESUs being in October, I also would have expected October to be ESU start.

I assume we will therefore get some of those ESUs also into the supported-os.json to be maintained like we do it now with Windows Server 2012? I assume ESU will be for Windows 10 22H2 (E) only (+ commercial Pro from (W))? With some LTS being longer than the ESU anyway.

[richlander]

Those assumptions seem sound. In general, if an OS has <6 months of support left when a new .NET release ships, we don't add it to our support list (for that .NET release). That's why Alpine 3.20 isn't listed as supported for .NET 10, even though Alpine 3.20 is a currently supported release.

I don't have a lot of depth on the ESU program. I expect that we'll continue to list ESU releases in supported-os.json/md, like you say.

With some LTS being longer than the ESU anyway.

I'm not sure what you mean by that.

[Falco20019]

With some LTS being longer [supported] than the ESU anyway.

I'm not sure what you mean by that.

The ESU is a paid program. So people can pay per year to continue using Windows 10 22H2 ESU for up to 3 years (until 2028 latest) once it reached general End-of-Support in 2025. Or they could downgrade to/stay on Windows 10 21H2 Enterprise LTS which has support until 2027 without additional costs. Or downgrade even more to Windows 10 1809 Enterprise LTS which has support until 2029 without paying (even longer than the 3 paid years of 22H2). Whereas Windows 10 21H2 Enterprise IoT LTS is supported until 2032...

So yeah, talking about straight-forward licensing ;) Some LTSC versions that were released later have shorter EOS. And ESU is somewhere in-between. This is mainly due to the existance of Mainstream EOS and Extended EOS which must not be confused for Extended Security Updates EOL.