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I'm developing an addin that uses msal-browser to implement SSO in a similar way to https://github.com/OfficeDev/Office-Add-in-samples/blob/main/Samples/auth/Outlook-Add-in-SSO-NAA-IE/README.md (though using a standard public client application instead of a nested one due to NAA specific issues tracked elsewhere).
My question is what are the potential cases for currently supported Outlook versions where this form of SSO is unavailable? I know that some versions of Outlook that use Trident/IE based webviews would have issues which would require a fallback like in that sample, but given that all of those Outlook versions seem to leave support by Oct 2025 we're fine with that given our timelines. Are there any other cases where SSO might not be supported that we should concern ourselves with?
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Hi Dan, The general availability status for NAA is documented here: https://learn.microsoft.com/en-us/javascript/api/requirement-sets/common/nested-app-auth-requirement-sets. We'll update that as NAA is GA on more platforms.
When NAA is not available, msal-browser will automatically fall back to using a public client application and use a dialog to sign in the user. However on some older Outlook clients there is a bug that causes an "about" error to show to the user. There's a fallback workaround for this in the sample https://github.com/OfficeDev/Office-Add-in-samples/tree/main/Samples/auth/Outlook-Add-in-SSO-NAA
Details are in the readme about fallback.
And for a list of which older platforms used the trident (IE11) webview, see https://learn.microsoft.com/en-us/office/dev/add-ins/concepts/browsers-used-by-office-web-add-ins
Cheers,
David
I've already read all those links and none of them answer my question. I'm not using NAA at all so it's availability is irrelevant, and I know IE11 webview is a case where I'd need to fallback to the Office dialog API. What I want to know is if there are any other cases where falling back to the office dialog API is the only way or if by Oct 2025 all currently supported versions of outlook will work without needing to fallback to the office dialog API
Hi Dan, well in October 2025, Outlook 2016 is end-of-life, so that will be out of support. Outlook 2019 uses IE11 webview and that will still be in support. You'll need to support an IE11 fallback scenario there. Windows 10 support also ends in October 2025, so I think you can ignore any scenarios in that table about Windows 10 and older Trident scenarios. Does this help? Thanks!
I though Outlook 2019 was also end of life in October 2025 https://learn.microsoft.com/en-us/lifecycle/products/outlook-2019, is there a different date for different editions (and where can I find it)?
Are there any scenarios besides a non-WebView2 webview that would cause SSO to not work?
Sorry, that's my bad, I wasn't reading that article carefully. You are correct and Outlook 2019 is also at end-of-life. I'm double-checking with the team if there would be any other Outlook clients still using IE11 after Oct 2025.
Hi Dan, sorry about that, I did not read the article correctly. You are correct that both Outlook 2016 and 2019 are at end-of-life in October 2025. I double-checked with the team, and confirmed there are no other Outlook clients supported beyond Oct 2025 that still use Trident/IE11 webview. So you can consider Trident/IE11 webview effectively end-of-life after Oct 2025.
Cheers,
David
Hope that helps
Confirmation that Trident/IE11 webviews are end-of-life after Oct 2025 is useful, but my main question is "are there scenarios where a WebView2 webview is being used that may cause SSO to fail and require the Office js dialog API fallback as implemented in https://github.com/OfficeDev/Office-Add-in-samples/tree/main/Samples/auth/Outlook-Add-in-SSO-NAA?"