Microsoft now offers an option in new Microsoft Edge browser Settings to enable IE mode. Edge Canary 86.0.580.0 or later versions contain this change.

Microsoft Edge team many times through social media made it clear that Internet Explorer Mode aka IE Mode is clearly for Enterprises or businesses (but not for end-users or consumers) to open a list of legacy sites in Internet Explorer.
In the past, Microsoft allowed users to enable the IE mode feature through a flag and command-line switch. Gradually the flag vanished and the command line switch has stopped working.
New Microsoft Edge for the first time is offering an option to enable IE Mode in its settings in the Canary version. Here is how you can turn it on and open some of the sites with Internet Explorer compatibility in Edge.
1. Launch new Microsoft Edge browser
2. Click on ellipsis > settings
3. Click Default browser and enable “Allows sites to be reloaded in Internet Explorer Mode”

4. Doing so adds the “Reload in Internet Explorer Mode” option in More tools under the ellipsis menu.
5. Click “Got it”
Visit a website, click on menu> More tools, and select the above-said option to load that site in IE mode.

To let you know you’re using IE Mode, Edge shows IE favicon in address bad and says “You’ve entered Internet Explorer Mode. Most pages work better in Edge.” with the option to Leave.
When you click “Leave “, the site gets reloaded with the blink engine in the new Edge browser.
Unless the changes appear in the Beta channel, there is no guarantee the feature will be released with the stable version, until then enjoy the IE mode in Edge by enabling the option provided in Default browser Settings.
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