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Admins, you've been warned: The clock is ticking on Edge's IE Mode

Microsoft has reminded administrators that Internet Explorer mode in Edge is guaranteed support only through 2029, so it is time to get those legacy migrations moving. Internet Explorer mode lets enterprises continue using legacy websites within Edge rather than relying on the retired Internet Explorer browser. It uses the Trident MSHTML engine from Internet Explorer 11 and per

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Utopia Tech

September 18, 2026 · 1 min read

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Microsoft has reminded administrators that Internet Explorer mode in Edge is guaranteed support only through 2029, so it is time to get those legacy migrations moving. Internet Explorer mode lets enterprises continue using legacy websites within Edge rather than relying on the retired Internet Explorer browser. It uses the Trident MSHTML engine from Internet Explorer 11 and permits elements such as ActiveX controls, although other Internet Explorer functionality, such as custom toolbars, is not supported.

Microsoft has promised to support IE mode until at least the end of 2029 and to provide one year's notice before retiring it. The feature is unlikely to stop working immediately after support ends, but organizations that depend on it could face security, compatibility, and compliance risks. A message in the Microsoft 365 admin center urges customers to begin modernizing legacy systems that still depend on Internet Explorer technology.

The company wrote: "Application modernization projects can take years to complete depending on the number and complexity of dependencies, so early planning reduces the risk of disruption later." Microsoft has been banging this particular drum for some time. It announced in 2021 that IE mode would be supported until at least the end of 2029, but its latest reminder suggests some customers still have substantial migration work ahead of them.

Administrators do not need to act immediately, but migrations involving old and heavily dependent applications can take years to complete. Internet Explorer debuted with the Plus! Pack for Windows 95 in 1995, but traces of it will survive for years yet.

Internet Explorer 11 is included with Windows 10 IoT Enterprise LTSC 2021, which remains supported until 2032, although Microsoft could retire Edge's IE mode considerably sooner. The end of 2029 might feel distant, but not to an enterprise facing a lengthy and potentially expensive migration from systems implemented decades ago.

Originally published at theregister.com

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