Microsoft will automatically remove your old Windows Edge browser starting April 13th by way of an update Microsoft is to replace the browser on that day with the new version based on Chromium, the software behind Google Chrome.
Users who have already downloaded the new Edge browser will not notice much. Only the old version is removed from them. It had been known for some time that Edge Legacy, made with technology from Microsoft itself, would no longer be supported from March 9. The classic Internet Explorer browser has not been updated since November last year. The new Edge has been available for download since 2019 and, according to Microsoft, offers better integration with Windows devices.
Knowing Microsoft, they'll try and default anything OS and everything Browser preference-based to their own browser though, please do be aware of that.
Chromium is currently the market leader in browser software, which means that most websites are optimized for Chromium browsers. This open-source technology is the basis of Chrome, Flock, and Opera, among others.