Microsoft is introducing a new Internet Explorer mode via the cloud & edge for legacy apps that still can only run under IE.  After June 2022, all IE support will end.

Microsoft Releases New Cloud Tool for Orgs Stuck on Internet Explorer — Redmondmag.com

Cloud Site List Management experience for IE mode in Microsoft Edge now generally available – Microsoft Edge Blog (windows.com)

With a little over 6 months left until the Internet Explorer 11 (IE11) desktop application retires on June 15, 2022, customers around the world like you are making the transition from the legacy IE11 browser to the more modern and secure Microsoft Edge browser with Internet Explorer (IE) mode. Microsoft Edge gives your organizations—and importantly, your users—a dual engine advantage that supports both legacy and modern websites. In fact, Microsoft Edge is the only browser that offers built-in support for legacy Internet Explorer-based websites and applications.

To help with the transition—and to help manage IE mode moving forward—we’ve been hard at work on new ways to simplify IE mode management. To that end, we are excited to announce that the Cloud Site List Management experience has moved out of preview and is now generally available for all customers.