When even Microsoft doesn't support it anymore, there's a Window of Opportunity to get the funding to make it happen
Any system that still require IE is outdated and thus likely a security risk, so identify those and do something about it. Identify the developer or vendor of those applications and have them updated.
If a vendor still only support IE or Flash or Silverlight, look elsewhere, they're not worth your time and money.
If you still require IE for some crappy internal application, blocking it from accessing the Internet (UserAgent "Mozilla/4.0 (compatible; MSIE*") will significantly lower your risk.
The upgrade recommendation on Github should be read from right-to-left if you want to protect your privacy too:
Worth reading too: