Believe it or not IE was still supported in some capacity until 2022, and the underlying Trident engine is still supported until at least 2029. Edge has an official "IE Mode" which switches the backend from Chromium to Trident, effectively turning it into IE with a modern skin. Microsoft support lifecycles are no joke.
For business plans the old Outlook is still supported until "at least 2029" [1]. That's four more years to switch. And Microsoft hasn't even committed to stopping support at that date, they just don't want to promise more. I fully expect them to extend it because some large customers won't have switched.
What is unusual is how pushy Microsoft is in trying to get people to switch now instead of in the last second. And of course the quick murder of the consumer email thingy
I specifically mean Windows Mail and Windows Calendar, the fairly minimalist apps, rather than Outlook, which is way too exhausting to use for my personal email and calendar. Plus the Outlook app has ads.
They'll support anything nearly forever if that's what their big support contracts want, but unfortunately their interests won't always align with yours...
This is useful to me because a) it still allows http basic auth, which is disabled by policy in my workplace for Edge/Blink, and b) because it otherwise allows dual logins and credentials to the same site, in the same browser.
The good news is that most of the web simply doesn't work in Trident at this point, so users won't be tempted to use it for anything other than the 20 year old ActiveX horror that their company refuses to replace.
