The End of Support Calendar shows Microsoft Operating Systems end of support dates, whether they are the end of mainstream support that updates features and cosmetic changes, or extended support, which ends security fixes and all Microsoft technical support other than old web pages.
Microsoft Edge Legacy End of Support in Office 365
Office 365 will stop supporting Microsoft Edge Legacy on March 9th, 2021. Microsoft Edge Legacy was forcibly replaced by Microsoft Edge Chromium in Windows 10 in April 2021, after a long period of recommending the change as optional.
As both the Legacy and Chromium products are identified everywhere in Windows as 'Edge', they can be told apart by their logos. From left to right, here are the logos for Internet Explorer, Edge Legacy, and Edge Chromium.