There will likely be cases where you have sites that were built for IE but are not caught up to Edge yet. What do you do in the interim? One idea that I applied on a legacy site was to inform take the Edge user to a specific page. You can always do a multitude of things when dealing with how to address the user (alerts, redirects, updates to labels on pages, etc.). I just want to show an easy way to detect and redirect.
The first thing you need to know is the Edge Browser’s User Agent String:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.135 Safari/537.36 Edge/12.9600
Place the following in a script tag inside of the head section of your html:
Hope it helps.