Update March 12, 2019: Since this post was published, I’ve received some customer questions on the future of Internet Explorer. We are committed to keeping Internet Explorer a supported, reliable, an...
Updated Mar 14, 2019
Version 6.0
Blog Post
>Also, how would you instruct Firefox\Chrome to open a site in IE?
Google has a feature to do this: https://support.google.com/chrome/a/answer/3019558?hl=en
"If your organization wants to take advantage of the Chrome Browser, but your users still need to access older websites and apps that require Internet Explorer, you can use this feature to easily switch between browsers. The Chrome Legacy Browser Support extension allows users to switch automatically between Chrome and another browser. When your user clicks a link that requires a legacy browser to open (such as a site that requires ActiveX), the URL will automatically open in the legacy browser from Chrome."
According to Chrome Web Store, there about 5.8M users today.
https://chrome.google.com/webstore/detail/legacy-browser-support/heildphpnddilhkemkielfhnkaagiabh?hl=en