IE 11, EdgeHTML Browsers Approaching End-of-Support Milestones

Microsoft this week announced key dates related to its support for the Internet Explorer 11 browser and the "legacy" (EdgeHTML) version of the Microsoft Edge browser.

Notably, IE 11 will stop working optimally with Microsoft 365 services on Aug. 17, 2021. After that August date, IE 11 will "have a degraded experience or will be unable to connect to Microsoft 365 apps and services," the announcement explained.

With regard to Microsoft 365 services, Microsoft specifically noted that Microsoft Teams will no longer have support for IE 11 on Nov. 30, 2020.

The milestone changes are summarized in this Microsoft graphic:

[Click on image for larger view.] End-of-support milestones for the Internet Explorer 11 browser and the EdgeHTML ("legacy) Microsoft Edge browser. (Source: Aug. 17 Microsoft 365 blog post)

Switch to Chromium-Based Edge
Microsoft wants organizations to switch to the new Chromium-based Microsoft Edge browser, which reached the "general availability" release status back in January.

Organizations won't be able to use the legacy Edge browser because it will be hitting its end-of-life stage early next year. Microsoft indicated that "after March 9, 2021, the Microsoft Edge Legacy desktop app will not receive new security updates." The browser will continue to work, but potentially Microsoft won't patch any of its security holes.

Microsoft claims high app compatibility with the new Chromium-based Edge browser. Here's Microsoft's claims on app compatibility, as described in its planning document:

  1. If it works on Microsoft Edge version 45 and earlier, it will work on Microsoft Edge version 77 and later.
  2. If it works on Internet Explorer, it will work on Microsoft Edge in Internet Explorer mode.
  3. If it works on Google Chrome, it will work on Microsoft Edge.

Microsoft has a FastTrack partner program for organizations with 150 or more Windows 10 Enterprise "seats" that will investigate app incompatibilities for no extra cost.

IE 11's Life Is Tied to Windows, But Not Edge
The lifespan of IE 11 is tied to the lifecycle of the underlying Windows operating system. IE 11 is "the last version of Internet Explorer," according to a Microsoft FAQ document. IE 11 ships on Windows 10, so if a version of Windows 10 is still supported, presumably IE 11 is supported, too. However, IE 11 still will lose support for Microsoft 365 services next year on Aug. 17, 2021.

Microsoft's announcement further clarified in a footnote that "Internet Explorer 11 is a component of the Windows operating system and follows the Lifecycle Policy for the product on which it is installed."

The Edge browsers, in contrast, follow the Modern Policy, where at best organizations get notified of a product change 30 days in advance. Microsoft established the Modern Policy four years ago, and it means whatever Microsoft wants it to mean.

One might think, recalling past antitrust litigation days, that Microsoft would argue that the Chromium-based Edge browser is a component of Windows 10, too, but the company doesn't make such an argument. Instead, Microsoft says that Edge gets updated independently of Windows 10, as if it were a separate product.

With the Modern Policy, Microsoft isn't committed to 10 years of support. It can kill products at will, and organizations will have to scramble. Hence the EdgeHTML legacy Edge browser is slated to fall out of support on March 9, 2021, which appears to be an arbitrary date.

Even though the new Chromium-based Edge browser isn't tied to Windows 10, organizations likely soon will find that they won't be able to delete the Edge browser from Windows 10 systems. Microsoft's January release of the Chromium-based Edge browser will replace the older legacy Edge browser. When that happens, you "can't uninstall Microsoft Edge." The new Edge browser arrives via Microsoft's Automatic Updates service when there are certain optional updates for Windows 10 installed, which are listed in this support article. Users of Windows 10 Enterprise and Education editions are excepted from this EdgeHTML-browser replacement policy.

Edge with IE Mode
For organizations using Web applications based on IE 11 technologies, Microsoft argues that it's possible to use the Chromium-based Edge browser with IE Mode, which lets IT pros specify which sites should render using IE 11 technologies. While IE Mode may work with an organization's older Web apps in this way, the coming end-of-support date of Nov. 30, 2020 for Teams and Aug. 17, 2021 for Microsoft 365 services still pertains.

Here's how the announcement expressed that point:

Note: Using Internet Explorer mode in the new Microsoft Edge will not help to extend IE 11 access to Microsoft 365 apps and services beyond the dates listed above. Microsoft 365 apps and services will stop supporting IE 11 on the dates listed.

Organizations stuck on IE 11 can use Microsoft's Enterprise Site Discovery tool to find sites that still have a dependency on IE 11, according to this Microsoft planning document.

About the Author

Kurt Mackie is senior news producer for 1105 Media's Converge360 group.