make Windows Terminal available to v1809

[fredless]

Summary of the new feature/enhancement

There are a significant quantity of corporate machines not able to run 1903 today for a variety of reasons (policy, compatibility, etc) and hence are locked out of terminal. I wasn't able to find much discussion about the reasons that exist for 1903 to be a requisite.

[JushBJJ]

In my guessing, there is probably a feature within the windows source code that is used in the new terminal which is why 1903 is required.

[ysc3839]

I guess it's because maintaining compatibility is a trouble. You CAN try to run on 1809 but without any support.

[DHowett-MSFT]

Sorry. Right now, there's two big blockers to adoption on 1809.

• XAML islands was a technology preview and didn't support high-DPI, DPI changes, or accessibility in 1809. We rely on them heavily.
• 1903 added support for side-by-side WinRT component activation, something deep in the COM stack that lets us find our DLLs when they're right next to our EXE.

We just can't go back to 1809.

[fredless]

We just can't go back to 1809.

TY for the detail

[brunofin]

We just can't go back to 1809.

Please Microsoft, fix the Surface Book 2 then so we can upgrade! 😭

[NetMage]

It looks like WInUI 3.0 will backport full XAML Islands support to most versions of Windows 10 and is releasing this year - could you use WinUI 3.0 to add support for Windows Terminal on earlier versions of Windows 10?

[zadjii-msft]

That's certainly a possibility we'd have to investigate. If XAML Islands was detached from the platform, then I'm not sure how many of our own features are actually dependent upon 1903.

I guess Dustin mentioned the SxS winrt activation above - I'm not positive that is still needed, but if it is, then that might be exceptionally hard for us to overcome. That would be one of the things to investigate when WinUI 3.0 is available.

[superm1]

WinUI 3.0

It seems to me that there is now a preview available for it: https://docs.microsoft.com/en-us/windows/apps/winui/winui3/

[zadjii-msft]

XAML Islands is not supported in this release

That's the single most important part of the WinUI stack we need, so unfortunately, that's a non-starter for us. Don't worry, we work pretty closely with the WinUI team (in the same hallway in fact), so when WinUI 3 is ready for us to move to it, we'll work on it 😉

[sidietz]

WinUI 3.0 Preview 2 has been released some days ago. Anything new on LTSC support?

https://docs.microsoft.com/en-us/windows/apps/winui/winui3/

[superm1]

Seems to still quote "XAML Islands is not supported in this release" on the preview 2 release notes.

[DHowett]

I've gone ahead and marked up their list of limitations with ones that stop us from being able to use Preview 2:

[zadjii-msft]

As I've said before, we won't be able to start experimenting with WinUI 3.0 until there's support for XAML Islands.

[driver1998]

Can we migrate the whole app to WinUI on Desktop instead of a Win32 Window with XAML islands?

[zadjii-msft]

@driver1998 At some point sure.

Last I checked (and this was a while ago), it would still be a while before WinUI3 supported custom content in the titlebar, and host backdrop acrylic. We fairly aggressively customize our own titlebar, and a lot of users really like acrylic and would be sad to see it go.

Now, that was a while ago, and priorities might have changed since then. So those features might be supported in the official first WinUI 3 release.

We've also got to balance the needs of our own engineering efforts. Moving to WinUI 3 would probably mean a whole month for a dev of just porting code and making sure nothing breaks. That's a month that we can't use on any of the other things that we've already committed to for Terminal v2. The WinUI 3 project layout is far nicer and will probably be better in the long run, but right now the Terminal's .sln is a bit of a house of cards. It's got a bunch of carefully constructed hacks in it to make sure the Terminal builds just right. Making sure those hacks still work in WinUI 3 is what would take the majority of the time.

WinUI 3 is probably one of the higher Terminal v3 priorities, it's just not in the cards for v2. We'd rather stick with the devil we know for now.

[sidietz]

After another three months having passed:
Is there any update on the WinUI3 transition?

[DHowett]

No, and it is neither in our roadmap nor committed or planned to ever happen. 😄

[chucker]

If I'm not mistaken, this means a Windows Server 2019 machine can't run Windows Terminal at all — the current release for that is still 1809. (And you can't do an in-place upgrade to a newer release, because those are on a different channel.)

[DHowett]

You are not mistaken.